PHYSIOLOGY 
AND  HEALTH 


CONN 


ONE  BOOK  COURSE 


SZLVER.BURDETT  &  COMPANY 


BIOLOGY 
LIBRARY 


4*~<*5 


* 


PHYSIOLOGY  AND  HEALTH 


ONE  BOOK  COURSE 


BT 

HERBERT   W.   CONN,   PH.D. 

*f 

PROFESSOR    OF    BIOLOGY   IN   WESLEYAN    UNIVERSITY 


SILVER,    BURDETT   AND    COMPANY 

BOSTON  NEW  YORK  CHICAGO 


PHYSIOLOGY  and  HEALTH  SERIES 


BOOK  ONE,  for  lower  grammar  grades,  224  pages. 
BOOK  TWO,  for  upper  grammar  grades,  384  pages. 
ONE-BOOK  COURSE,  448  pages. 

ADVANCED    PHYSIOLOGY    AND     HYGIENE, 
for  High  Schools,  420  pages. 


BIOLOGY 
LIBRARY 

G 


- 


COPYRIGHT,  1916,  BY  SILVER,  BURDETT  AND  COMPANY. 


PREFACE 

WHEN  the  study  of  the  human  body  was  first  introduced 
into  our  schools,  it  was  anatomy  that  was  chiefly  emphasized. 
After  a  generation  of  experience  a  change  from  anatomy  to 
physiology  —  from  structure  to  function  —  appeared,  and  the 
school  textbook  became  primarily  a  physiology.  Later  still 
it  was  felt  that  health  —  both  personal  and  public  health  — 
should  be  the  primary  aim  of  the  study  of  the  subject,  and 
textbooks  began  to  put  both  anatomy  and  physiology  entirely 
in  the  background  so  as  to  bring  to  the  front  problems  of 
health  and  disease. 

In  this  textbook  it  has  been  the  endeavor  of  the  author 
not  to  lose  sight  of  the  necessary  knowledge  of  the  funda- 
mentals of  physiology  and  anatomy  and  to  retain  the  primary 
essentials  of  physiology,  but  at  the  same  time  to  place  large 
emphasis  upon  personal  and  public  hygiene.  The  study  of 
disease  seems  to  have  no  place  in  the  public  schools  except 
in  so  far  as  needed  to  assist  the  child  in  appreciating  and 
adopting  such  a  regulation  of  his  life  as  will  aid  him  in 
avoiding  disease.  The  preventable  diseases,  therefore,  are 
freely  considered,  special  reference  being  given  to  their  pre- 
vention, while  the  non-preventable  diseases  are  either  omitted 
or  just  mentioned,  not  discussed. 

In  early  years,  the  author  felt  that  an  apology  was  almost 
needed  every  time  he  mentioned  bacteria  and  germ  diseases. 
But  to-day  these  subjects  hold  such  a  prominent  place  in 

iii 

358866 


iy  PREFACE 

health  discussions  that  no  emphasis  within  the  understanding 
of  a  child  can  be  considered  too  great. 

The  new  facts  that  have  been  established  in  connection 
with  foods  have  changed  many  features  of  that  important 
subject.  Even  the  relation  of  bones  and  muscles  presents 
a  new  emphasis  to  be  placed  upon  certain  topics,  especially 
such  as  relate  to  properly  shaped  feet  and  the  results  of 
muscle  degeneration.  The  recognition  of  neurons  as  the 
units  of  the  nervous  system  and  nervous  action,  and  the  con- 
ception of  the  brain  and  spinal  cord  as  a  complex  of  inter- 
related neurons,  have  vastly  illuminated  the  study  of  the 
nervous  system  even  for  younger  children. 

The  advance  that  has  been  made  in  the  one  subject  of 
hygiene  is  astonishing.  Many  essential  facts  have  been  so 
widely  verified  that  it  is  now  possible  to  state  them  in  the 
definite,  clear-cut  form  that  must  be  used  in  the  instruction 
of  pupils  below  the  high  school  age.  There  is  sufficient 
valuable  data  to  lead  to  a  widespread  revolution  in  the  habits 
of  life  in  this  country  if  those  facts  could  be  brought  home 
to  the  boys  and  girls  in  the  grammar  grades.  How  they 
should  live ;  what  they  should  eat ;  what  they  need  in  the 
way  of  work  and  play;  why  and  how  they  should  study  — 
on  these  points  and  on  many  others  the  teachings  are  definite 
and  clear.  The  question  now  is  how  to  make  the  facts  live 
in  the  minds  of  our  young  people ;  if  rightly  used,  they  are 
a  rich  heritage. 

The  aim  of  this  textbook  is  to  treat  physiology  and  health 
in  the  light  of  the  most  recent  information  possible,  to  make 
the  facts  usable,  to  present  them  so  simply,  so  directly,  and 
so  naturally  as  a  part  of  the  field  of  opening  knowledge  that 
what  his  parents  know  yet  disregard  the  child  will  believe 
and  follow.  No  books  could  accomplish  this  without  the 


PREFACE  V 

earnest  and  intelligent  efforts  of  the  teacher  to  reenforce  and 
supplement  what  printed  words  can  say.  The  results  that 
might  follow  from  the  success  of  such  teaching  are  too 
evident  to  need  enumeration ;  the  need  for  such  instruction 
was  never  more  clear  than  now ;  the  means  to  the  end  were 
never  before  so  abundant. 

This  One  Book  course  is  designed  for  schools  where  it  is 
not  desired  to  introduce  physiology  into  the  lower  grades. 
The  addition  of  a  few  extra  pages  makes  it  possible  to  give 
a  more  comprehensive  and  satisfactory  treatment  of  matters 
of  Personal  and  Public  Hygiene,  which  it  is  believed  will  be 
useful  in  training  children  for  citizenship. 


CONTENTS 

SECTION   I 

FEEDING   THE  BODY 

CHAPTER 

PA<.K 

I. 

WHY  WE  NEED  FOOD  .        .        .        .        .        •  .  .  |  - 

1 

IT. 

WHAT  WE  NEED  IN  FOOD  . 

.5 

III. 

15 

IV. 

FOODS  WE  GET  FROM  PLANTS    .        .        . 

.      21 

V. 

THE  PURCHASE  AND  CARE  or  FOOD  . 

.      26 

VI. 

BEVERAGES     .        .        .        .        .        .        . 

.      32 

VII. 

THE  FIRST  STEP  IN  DIGESTION  .        .        .        ... 

.      41 

VIII. 

DIGESTION  IN  THE  STOMACH        .        .        . 

.      53 

IX. 

DIGESTION  AND  ABSORPTION  IN  THE  INTESTINES 

.  -    61 

X. 

70 

XL 

INTELLIGENT  COOKING  

.       82 

XII. 

INTELLIGENT  FIGHTING  OF  THE  BODY'S  FOES  . 

.       89 

SECTION    II 

WHAT   THE   BODY   DOES  WITH   ITS   FOOD 

I. 

How  THE  BLOOD  CARRIES  THE  FOOD 

.     101 

II. 

THE  HEART  AND  THE  CIRCULATION  .... 

.     108 

III. 

THE  CONTROL  OF  THE  BLOOD  FLOW  . 

.     116 

IV. 

WHAT  BREATHING  DOES      

.     131 

V. 

VENTILATION  :   ARTIFICIAL  RESPIRATION  . 

.     150 

VI. 

SOME  OF  THE  NATION'S  UNSEEN  FOES 

.     165 

VII. 

How  THE  BODY  Is  MADE  MOVABLE  .... 

.     186 

vii 

viii  CONTENTS 


CHAPTER 

VIII. 

BONES  AND  JOINTS        

PAGE 

197 

IX. 

EXERCISE:   STRENGTH  AND  GRACE  OF  BODY     . 

213 

X. 

REMOVAL  OF  BODY  WASTES         V 

227 

XI. 
XII. 
XIII. 

STRUCTURE  AND  FUNCTIONS  OF  THE  SKIN 
TAKING  CARE  OF  THE  SKIN         .         .        .        .        .        . 

233 
247 
259 

SKIN  DEFECTS  AND  DISEASES      

SECTION    III 

HOW   THE   BODY   IS   GOVERNED 

I. 

THE  GOVERNING  MECHANISM      

273 

II. 

INVOLUNTARY  AND  REFLEX  ACTIONS 

289 

III. 

BETTER  GOVERNMENT  OF  THE  BODY  

302 

IV. 

INTERFERENCE  WITH  THE  CONTROL  OF  THE  BODY   . 

315 

V. 

THE  PART  PLAYED  BY  THE  SPECIAL  SENSES:    SIGHT 

324 

VI. 

THE  PART  PLAYED  BY  THE  SPECIAL  SENSES  (Continued)  : 
HEARING  AND  OTHER  SENSES      

335 

SECTION    IV 

PERSONAL   AND   PUBLIC   HEALTH 

I. 

THE  CAUSES  OF  ILL  HEALTH      

349 

II. 

HEALTH  HABITS  AND  OCCUPATIONS  

361 

III. 

PUBLIC  HEALTH  AND  HEALTH  OFFICIALS 

374 

IV. 

How  OUR  FOOD  AND  DRINK  is  GUARDED 

381 

V. 

How  THE  COMMUNITY  is  KEPT  CLEAN  AND  WHOLESOME 

393 

VI. 

How  THE  SPREAD  OF  EPIDEMICS  is  CHECKED  . 

402 

VII. 

MEETING  EMERGENCIES         .        .        * 

417 

GLOSSARY  OF  TECHNICAL  TERMS    
INDEX 

425 
433 

PHYSIOLOGY   AND   HEALTH 

SECTION  I 
FEEDING  THE  BODY 

CHAPTER  I 

WHY   WE   NEED   FOOD 

Why  We  Eat.  —  We  eat  because  we  are  hungry ;  and 
we  are  hungry  because  our  bodies  need  food.  Why  do 
they  need  food  ?  How  do  they  use  it  ?  In  the  first  place, 
our  bodies  are  always  in  action.  We  may  sit  very  still, 
without  speaking,  without  seeming  to  move  a  muscle, 
yet  all  the  time  many  parts  of  our  bodies  are  hard  at 
work.  There  are  some  parts  that  work  all  night  and  all 
day,  whether  we  are  awake  or  asleep. 

The  body  has  been  called  the  most  wonderful  of  all 
engines.  Engines  cannot  run  without  fuel ;  some  burn 
shavings,  others  burn  coal,  for  others  gasoline  is  needed. 
If  one  wishes  to  make  any  kind  of  engine  run  properly, 
he  must  know  with  what  fuel  to  feed  it ;  and  he  must  also 
know  what  to  do  when  some  part  of  the  machine  wears 
out  and  needs  to  be  repaired. 

The  Two  Kinds  of  Food.  —  Unlike  other  machines, 
the  body  gets  from  the  materials  fed  to  it  both  the  fuel 

1 


PHYSIOLOGY 'AND   HEALTH 


with  which  to  work  and  the  substances  necessary  for 
replacing  worn-out  parts.  The  body  must  find,  then, 
in  its  food  :  (1)  fuel  to  give  it  energy  for  work ;  (2)  mate- 
rials for  making  repairs.  By  "  food  "  we  mean  only  such 
portions  of  what  we  eat  as  the  body  can  use  for  repair  or 
for  fuel.  We  shall  not  class  as  "  food,"  materials  that 
injure  any  part  of  the  body  or  that  pass  out  of  it  as 
waste. 

Foods  for  Building  and  Repair.  —  In  comparing  the 
body  to  a  machine,  we  must  notice  another  difference.     A 


An  automobile  needs  gasoline  for  power  and  a  variety  of  other  substances  for 

repairs. 

machine  is  perfected  before  it  begins  its  work ;  the  body 
is  not.  The  body  of  the  new-born  baby  must  not  only 
do  its  work,  but  it  must  also  build  up  and  perfect  its 
parts  —  that  is,  it  must  grow  and  develop  before  it  can 
become  the  full-sized,  perfectly  adjusted  body  of  an  adult. 
Nor  does  it  wholly  stop  growing  even  when  it  reaches  full 
size.  Certain  parts  of  it,  like  the  hair  and  the  finger  nails, 
keep  on  growing,  and  the  skin  is  constantly  growing  to 
replace  what  is  worn  away.  In  the  grown  man,  the 
muscles  and  bones  have  stopped  growing  larger,  yet  they 
wear  out  as  they  work  and  so  need  constant  repairing. 


WHY  WE  NEED   FOOD  3 

Perhaps  you  had  never  thought  of  the  bones  and  muscles 
as  workers,  but  that  is  what  they  are ;  and  they  must 
have  food  that  will  repair  them. 

Fuel  Foods.  —  Fuel  foods  furnish  the  body  with  heat 
and  power.  If  we  ate  no  fuel  food,  the  body  could  not 
be  kept  warm,  even  in  a  hot  room,  and  with  very  heavy 
clothes  on.  Nor  would  it  have  the  power  needed  to 
move  the  muscles,  or  to  keep  the  other  parts  of  the  body 
at  work.  It  could  not  live.  Does  this  mean  that 
whenever  we  feel  cold  we  ought  to  go  quickly  and  get 
some  fuel  food  ?  No,  indeed ;  for  in  that  respect  our 
feelings  do  not  count ;  what  counts  is  the  temperature 
of  the  blood.  Though  we  may  feel  cold  in  winter  and 
hot  in  summer,  the  heat  of  our  bodies  (i.e.  of  the  blood) 
is  really  the  same,  summer  and  winter.  The  normal 
temperature  of  the  blood  is  98.6°  F.  When  it  drops  below 
that  point,  we  are  ill ;  and  a  rise,  even  of  one  or  two  degrees, 
above  that  point  produces  fever.  We  do  not  need  to  watch 
our  temperature,  however ;  for  if  we  live  right  and  keep 
well,  it  will  take  care  of  itself. 

Combustion.  —  By  watching  the  fire  in  a  stove,  we 
get  some  idea  of  how  the  food  we  eat  keeps  us  warm  and 
gives  our  bodies  power.  When  the  fuel  in  a  stove  is 
burning,  we  see  a  flame  ;  it  is  caused  by  the  uniting  of  the 
fuel  with  a  gas  in  the  air  (oxygen).  This  is  called  com- 
bustion. In  this  case  it  produces  both  heat  and  flame. 
Other  substances  which  burn  more  slowly  give  off  heat 
without  making  any  flame.  Wherever  there  is  com- 
bustion there  must  be  a  substance  that  will  burn,  and 
there  must  be  oxygen  to  unite  with  it.  Fuel  foods  are 
burned  in  our  bodies,  slowly  and  without  any  flame,  the 


4  PHYSIOLOGY  AND   HEALTH 

necessary  oxygen  being  taken  into  the  body  with  the  air 
we  breathe. 

QUESTIONS 

1.  What  is  going  on  in  your  body  when  you  are  sitting  perfectly 
still?     Mention  as  many  things  as  you  can. 

2.  What  are  the  two  uses  of  food? 

3.  What  is  some  of  the  repair  work  that  the  body  is  constantly 
doing? 

4.  Does  a  person's  occupation  have  any  effect  upon  the  amount 
of  food  required  ? 

5.  In  what  respects  is  the  body  a  more  wonderful  machine  than,  the 
most  complicated  one  that  man  can  devise? 

6.  Why  do  you  think  a  child  is  likely  to  get  hungry  more  often 
than  is  a  grown  person? 

7.  If  you  should  place  a  thermometer  in  the  mouth,  what  tempera- 
ture'would  it  show  in  summer?    What  in  winter?    Would  the  ther- 
mometer tell  whether  you  felt  warm  or  cold  ? 

8.  Is  there  any  difference  in  the  amount  of  food  required  in  summer 
and  in  winter?     Why? 

9.  What  is  combustion?    Is  there  any  difference  between  combus- 
tion in  the  stove  and  in  the  body?     If  food  is  burned  in  the  body,  why 
are  there  no  flames? 


CHAPTER  II 

WHAT   WE   NEED   IN   FOOD 

Where  Animals  Get  their  Food.  —  It  is  clear  that  food 
must  contain  whatever  is  necessary  to  build  (and  repair) 
the  body,  and  to  give  it  heat  and  power.  We  speak  of 
matter  as  divided  into  three  "  kingdoms," — mineral, 


FIG.  1.  —  A  WHEAT  FIELD. 

vegetable,  and  animal.  The  vegetable  kingdom  derives 
its  nourishment  largely  from  the  mineral  kingdom;  the 
animal  kingdom  derives  its  nourishment  from  the  vege- 
table kingdom,  or  from  other  animals  that  feed  upon  plants. 

5 


6  PHYSIOLOGY   AND   HEALTH 

Man  is  no  exception  to  the  rule  ;*  he  has  learned  a  great 
deal  about  minerals  and  how  to  utilize  them,  but  he  has 
never  discovered  how  to  derive  nourishment  from  them. 
Like  the  rest  of  the  animal  kingdom,  man  has  to  depend 
for  his  food  either  upon  the  vegetable  kingdom  or  upon 
other  animals.  Plants  are  the  only  real  food  factories 
in  the  world ;  they  make  all  the  food  they  need  for  them- 
selves, and  also  all  the  food  for  the  animals. 

Three  Kinds  of  Food.  —  The  foods  that  men  use  have 
been  divided  into  three  groups;  the  different  members 
/>f  each  group  serve  the  same  purpose  in  the  body  and  have 
essentially  the  same  constituents,  although  they  may  not 
look  alike  or  taste  at  all  alike.  The  names  given  to 
these  groups  are : 

Proteins 

Carbohydrates 

Fats 

Proteins.  —  The  foods  that  serve  to  build  up  the  body, 
and  to  keep  it  in  repair,  are  called  proteins ;  without  them 
the  body  would  starve.  They  can  also  be  used  as  fuel 
to  a  certain  extent ;  but  their  fuel  value  is  the  least 
important,  since  we  can  get  our  fuel  foods  in  many  other 
forms  while  we  cannot  get  building  material  from  any- 
thing except  the  proteins. 

If  you  wanted  to  buy  some  proteins,  you  might  go  to 
the  meat  market,  to  the  fish  market,  to  the  grocer,  to  the 
fruit  and  vegetable  store  —  they  all  sell  proteins,  but 
you  could  not  get  what  you  wanted  by  asking  for  a 
quarter's  worth  of  proteins.  A  chemist,  if  you  went 
to  him,  would  want  to  know  what  kind  of  proteins  you 


WHAT  WE  NEED   IN  FOOD 


wished,  for  they  have  different  names  when  they  appear 
in  different  substances.  The  following  table  gives  some 
of  them. 


PROTEIN  IN 
White  of  egg 

Lean  meat 

Flour 

Milk 


Is  CALLED  How  IT  LOOKS 

Albumen  White,  transparent,  jellylike;  heat 
makes  it  become  solid,  i.e.  coagulates 
it. 


Myosin 


Gluten 


Casein 


Peas  and  beans         Legumin 


Soft  and  elastic  when  uncooked ;  cook- 
ing coagulates  it,  like  the  albumen 
in  the  egg. 

A  sticky,  gummy  mass  ;  may  be  separ- 
ated by  letting  water  run  through  a 
little  muslin  bag  filled  with  flour. 

The  curd  of  milk,  a  thick,  whitish 
substance.  To  see  it  in  sweet  milk, 
pour  in  a  little  vinegar.  Cheese  is 
prepared  curd. 

Similar  to  gluten.     Is  also  in  peanuts. 


If  we  were  in  a  place  where  we  could  not  get  a  single 
one  of  the  substances  in  the  foregoing  table,  we  might 
still  find  plenty  of  protein,  since  it  is  contained  in  all 


Flour 


Dough 


Gluten 


FIG.  2.  —  WHEAT  FLOUR. 

Showing  the  amount  of  dough  to  be  obtained  from  a  quart  of 
flour,  also  the  amount  of  gluten  to  be  obtained  from  the  same 
quantity  of  flour. 


8  PHYSIOLOGY  AND   HEALTH 

classes  of  food.  The  table  on  page  87  lists  the  most 
common  foods  and  gives  the  amount  of  protein  in  each  of 
them.  A  glance  at  the  list  will  show  that  the  largest 
amount  of  protein,  per  pound,  is  contained  in  meat,  eggs, 
cheese,  peas,  and  beans. 

Carbohydrates. --The  most  abundant  fuel  foods  are 
called  carbohydrates;  these  include  all  starches  and 
sugars.  Sugar  and  starch  seem  to  us  very  different,  but 
in  reality  they  are  much  alike.  Nature  is  constantly 
busy  changing  starch  into  a  delicious  sugar.  That  is 
what  happens  whenever  green  fruit  ripens,  and  a  similar 
change  happens  in  our  bodies.  When  we  eat  starchy 
food,  like  potatoes,  the  starch  is  changed  into  a  kind  of 
sugar,  by  a  process  called  digestion.  This  does  not  mean 
that  since  sugar  tastes  better  than  starch  we  might  as 
well  take  all  the  carbohydrates  we  need  in  the  form  of 
sugar;  that  would  not  answer,  and  the  reason  why  will 
be  apparent  later. 

The  carbohydrates  (like  the  fats)  are  useful  only  for 
fuel ;  they  cannot  do  any  of  the  building  or  repairing 
of  the  body.  But  the  body  requires  so  much  power  with 
which  to  do  its  work  that  more  of  .fuel  food  is  needed  than 
of  building  food;  that  is,  more  of  the  carbohydrates 
and  the  fats  than  of  the  proteins.  In  considering  foods, 
we  shall  now  need  to  think,  not  how  they  taste  or  look, 
but  which  of  the  food  elements  they  contain. 

Starch.  —  When  starch  is  spoken  of  as  a  fuel  food,  we 
mean  starch  as  it  is  contained  in  the  vegetables  and 
the  grains;  to  use  such  substances  as  food  we  do. not 
have  to  separate  the  starch.  Indeed,  it  is  better  to  eat 
the  whole  of  the  grain  than  to  eat  the  starch  after  it  is 


WHAT   WE   NEED   IN  FOOD 


9 


removed  from  the  grain.  The  starch  in  wheat  makes  it 
look  white,  and  it  gives  the  white  appearance  to  potatoes 
and  to  corn;  yet  all  vegetables  that  contain  starch  do 
not  look  white.  Test  this  by  putting  a  drop  of  iodine  on 
a  freshly  cut  piece  of  potato ;  if  the  spot  touched  turns 
blue,  it  means  that  there  is  starch  there.  Now  test  some 
of  the  green  vegetables,  like  spinach  and  lettuce.  Do 
you  find  that  they  contain  starch?  (If  they  do,  the 
spot  touched  with  iodine 
will  look  bluish.)  In  the 
same  way  test  a  little 
flour. 

The  presence  of  starch 
can  also  be  detected  with 
a  microscope,  for  starch 
is  made  up  of  grains, 
which  show  very  plainly 


under  the  microscope. 
The  grains  in  Figure  3 
are  of  different  sizes  and 


Potato 


Bean 


Shapes,   but   they   Can  all    FlG«  3.  — STARCH  GRAINS  FROM  VARIOUS 
-i  •      j  FoODS- 

be   easily  recognized   as 

starch  grains.  When  we  put  starch  into  a  little  water 
and  boil  it,  we  can  no  longer  find  the  starch  grains ;  for 
the  heat  makes  them  swell  and  burst,  and  the  starch 
becomes  a  thick  paste. 

Sugar.  —  In  this  country  sugar  is  so  plentiful  that 
every  one  knows  how  it  looks  and  tastes,  but  there  are 
countries  in  which  it  is  so  scarce  that  children  rarely 
have  any.  Most  sugar  comes  from  certain  plants,  and 
if  those  plants  do  not  grow  in  a  country,  its  people  have 


10 


PHYSIOLOGY   AND   HEALTH 


only  such  sugar  as  they  can  afford  to  buy  and  bring  in 
from  other  countries.  The  following  list  gives  the  sources 
of  our  sugars.  How  many  grow  in  this  country? 


NAME 
Cane  sugar 


Beet  sugar 
Fruit  sugar 

Glucose 


OBTAINED  FROM 
Sugar  cane 


Sugar  beets 

Grapes  and  other 
fruits 

Manufactured  from 
corn  and  other 
starchy  substances 


COMMENTS 

Cane  sugar  is  prepared  in  many 
ways  —  as  granulated  sugar, 
powdered  sugar,  cut  sugar, 
brown  sugar,  molasses. 

Tastes  and  looks  like  cane  sugar. 
Not  so  sweet  as  cane  sugar. 

Much  like  fruit  sugar,  and  not  so 
sweet  as  cane  sugar. 


Milk  sugar  should  also  be  mentioned ;  it  is  obtained 
from  the  milk  of  animals,  and  is  even  less  sweet  than 
fruit  sugar. 

Glucose.  —  One  might  think  that  the  sweetest  sugar 
would  be  the  best,  and  would  make  the  best  fuel  food ; 
but  it  has  been  found  that  all  the  sugars  have  about  the 
same  food  value.  That,  however,  does  not  prove  that 
they  are  all  equally  useful.  Did  you  notice  in  the  list 
a  sugar  called  glucose,  made  from  starch?  It  seems 
wonderful  that  men  should  be  able  to  change  starch  into 
sugar;  and  it  is  only  within  recent  years  that  manu- 
facturers have  learned  how  to  make  this  change.  The 
glucose  that  is  now  made  is  wholesome,  but  it  is  not 
nearly  so  sweet  as  cane  sugar.  It  is  frequently  mixed 
with  cane  sugar  because  it  is  much  cheaper;  by  selling 
sugar  with  glucose  in  it  the  dealer  can  make  more  profit. 
But  we  buy  sugar  chiefly  for  its  sweetness.  A  pound 
of  the  mixture  will  not  do  as  much  sweetening  as  it 


WHAT  WE  NEED   IN  FOOD  11 

ought,  and  so  when  people  buy  it,  they  are  not  getting 
their  money's  worth. 

Fats.  —  Foods  of  the  third  class  (fats)  are  richer  in 
fuel  than  either  the  starches  or  the  sweetest  sugar.  The 
fats  and  oils  give  about  twice  as  much  heat  per  pound 
as  any  other  food.  Some  of  them  come  from  animals  and 
some  from  the  vegetable  kingdom.  The  following  table 
lists  a  few  of  the  .fatty  foods.  Add  as  many  others  as 
you  can,  and  name  the  source  of  each. 

FROM  ANIMALS  FROM  PLANTS 

Butter  Olive  oil 

Lard  Cottonseed  oil 

Tallow  Peanut  oil 
Blubber 

Notice  that  the  vegetable  fats  (oils)  are  in  liquid  form 
—  they  are  a  part  of  the  juice  of  the  fruit  from  which 
they  are  taken.  The  animal  fats,  like  the  butter  and  the 
lard  we  buy  in  the  market,  usually  come  to  us  in  solid 
form,  but  in  their  original  state  they  are  liquid  too.  The 
fat  of  the  sheep,  from  which  tallow  is  made, 
is  a  transparent  liquid  in  the  living  animal ; 
and  this  is  true  of  the  other  animal  fats. 

The  little  drops  of   animal  fat  are  each 
inclosed  in  a  tiny  sac.     Figure  4  shows  a    FlGt  4._FAT 
group  of  fat  cells  taken  from  the  fatty  part        CELLS. 
of   a  piece    of   beefsteak;    these   are    much    Obtained  from 

.  a  bit  of  meat. 

too  small  to  be  seen  without  a  microscope. 
One  of  the  properties  of  a  fat  is  that  it  will  break  into 
tiny  droplets  if  shaken  with  certain  liquids.     Put  a  few 
drops  of  olive  oil  into  a  small  bottle,  add  some  water,  put 


12  PHYSIOLOGY  AND   HEALTH 

in  the  cork,  and  shake  the  mixture  rapidly.  See  how  it 
looks  after  shaking ;  then  let  it  stand  for  an  hour  and  note 
the  change.  In  every  glass  of  milk  there  are  millions  of 
fat  drops ;  when  the  milk  stands,  they  separate  from  the 
rest  of  the  liquid,  rise  to  the  surface,  and  form  cream. 

Mixed  Foods.  —  In  order  to  keep  well  and  strong  we 
must  have  the  three  kinds  of  food  —  proteins,  carbohy- 
drates, fats.  The  question  now  is,  in  what  form  it  is 
best  to  eat  them  and  how  much  of  them  we  need.  The 
answer  would  be  easier  if  all  our  foods  were  not  mixed 
foods ;  nearly  everything  we  eat  contains  all  three  kinds 
(see  Figure  24). 

Bread  and  butter,  for  example,  which  most  of  us  eat 
every  day,  seems  a  very  simple  food;  but  watch  the 
bread  making,  some  time,  and  see  how  many  things  go 
into  the  bread.  You  will  probably  find  that  it  is  made 
with  flour,  milk,  lard  (or  butter),  a  little  sugar,  and  some 
salt.  There  are  five  ingredients  besides  the  yeast  (or 
baking  powder)  that  is  used  to  "  raise  "  it ;  and  those 
five  contain  different  food  substances.  The  flour  gives 
a  carbohydrate,  starch,  and  a  little  protein  in  the  form 
of  gluten ;  the  milk  gives  another  protein,  casein,  and  a 
carbohydrate,  sugar, 'and  some  fat;  the  lard  gives  fat, 
and  the  butter  on  the  bread  adds  still  more  fat ;  the  cane 
sugar  is  still  another  carbohydrate.  How  many  kinds  of 
proteins,  carbohydrates,  and  fats  are  there  in  a  slice  of 
bread  and  butter? 

Comparative  Food  Values.  —  Since  plain  bread  and 
butter  proves  to  be  such  a  mixed  food,  we  might  well  won- 
der whether  it  would  ever  be  possible  to  discover  how  to 
get  the  right  quantities  of  the  three  kinds  of  food.  The 


WHAT   WE   NEED   IN  FOOD 


13 


first  step  is  to  discover  the  comparative  amounts  of  pro- 
tein, carbohydrates,  and  fats  in  our  common  foods.  Much 
has  been  done  in  the  laboratories  to  simplify  that  problem 
for  us. 

The  results  of  these  experiments  with  proteins  in  various 
forms  are  given  in  Figure  5.     The  same  amount  of  protein 


Beans 


Eggs 


Mifo 


Cheese 


Steak 


Rolled  Oats 


Potatoes 


FIG.  5.  —  FOODS  CONTAINING  EQUAL  AMOUNTS  OF  PROTEINS. 

The  amount  of  protein  in  each  of  these  food  portions  is  the  same. 
For  example,  1  pt.  of  milk  contains  as  much  protein  as  2£  oz.  of 
beans,  6  slices  of  bread,  2  oz.  of  cheese,  5  oz.  of  steak,  etc. 


is  found  in  the  various  quantities  of  different  foods  there 
represented.  It  will  be  seen,  for  instance,  that  a  small 
piece  of  cheese  (two  ounces)  contains  as  much  protein  as 
is  found  in  six  slices  of  bread  or  in  three  eggs  and  that 
the  protein  in  a  handful  of  peanuts  is  equal  to  that  in  five 
ounces  of  steak.  Similar  information  has  been  compiled 
about  the  fats  and  the  carbohydrates. 


14  PHYSIOLOGY   AND   HEALTH 

QUESTIONS 

1.  What  is  the  original  source  of  all  our  food?    Can  man  manu- 
facture food? 

2.  Mention  foods  that  are  good  for  horses  that  are  not  good  for 
men. 

3.  Mention  some  animals  that  live  wholly  upon  plant  foods ;  some 
that  live  wholly  upon  animal  foods. 

4.  Do  proteins  belong  to  the  animal  or  the  vegetable  kingdom 
or  to  both?    If  the  latter,  give  examples. 

5.  What  are  proteins  used  for  in  the  body? 

6.  What  class  of  foods  is  especially  needed  by  growing  children? 
Why? 

7.  What  foods  furnish  fuel  for  the  body? 

8.  What  is  the  chief  article  of  food  in  the  Eskimo's  diet?    How 
do  you  account  for  this? 

9.  What  proteins  did  you  eat  for  dinner?     For  supper  last  night? 

10.  What  carbohydrates  did  you  eat  for  lunch? 

11.  What  makes  starch  paste  thicken  when  boiled?     Do  you  know 
of  any  other  food  that  swells  up  greatly  when  heated  ?     What  happens 
when  corn  is  popped? 

12.  Was  there  any  sugar  in  your  lunch?     If  so,  of  what  kind  was 
it,  and  where  did  it  come  from? 

13.  Why  do  we  not  want  glucose  in  our  sugar? 

14.  What  fats  did  you  eat  for  dinner  and  what  was  their  source? 

15.  What  is  the  difference  between  cream  and  butter? 

16.  How  much  bread  would  you  have  to  eat  to  give  you  as  much 
protein  as  there  is  in  a  pint  of  milk?    How  many  eggs ? 


CHAPTER   III 
FOODS   WE    GET   FROM    ANIMALS 

Sources  of  Foods.  —  Comparing  plant  and  animal 
foods,  it  may  be  said  that  animal  food  contains  more 
protein  and  less  carbohydrate  ;  plant  food,  more  carbohy- 
drate and  less  protein.  Both  contain  fats.  The  principal 
foods  that  are  supplied  to  us  by  animals  —  meat,  eggs, 
and  milk  —  are  rich  in  protein,  but  they  are  much  more 
expensive  than  the  plant  foods  that  also  give  abundant 
protein. 

Protein  in  some  form  is  absolutely  essential  to  life ;  it 
may  be  used  in  the  body  as  fuel  as  well  as  a  building  food. 
This  statement  might  suggest  that  a  diet  of  proteins 
alone  would  be  the  most  desirable,  if  one  could  afford 
it ;  but  that  is  far  from  being  the  case,  for  too  much  pro- 
tein is  almost  as  bad  as  too  little.  We  shall  later  learn 
the  reason  for  this,  and  also  why  plant  proteins,  being 
cheaper,  are  not  universally  used  as  substitutes  for  the 
more  expensive  animal  proteins. 

Milk.  —  Think  how  many  months  a  baby  grows  larger, 
and  gets  strong  and  fat,  with  no  food  except  milk.  Milk 
evidently  must  contain  all  that  the  baby  needs,  in  the 
right  proportions.  Look  down  the  table  on  page  87  for 
a  food  that  contains  protein,  carbohydrate,  and  fat  in 
nearly  equal  proportions ;  the  only  one  that  meets  these 
requirements  is  —  milk.  The  curd  (which  we  know  as 

15 


16  PHYSIOLOGY   AND   HEALTH 

casein)  is  the  building  food  ;  the  cream,  which  is  a  fat,  is  a 
fuel  food,  as  is  also  the  milk  sugar,  which  is  a  carbohydrate. 

When  the  baby  becomes  more  active  and  begins  to 
walk,  he  needs  more  fuel  food  than  there  is  in  milk. 
Then  he  can  use  up  force  faster  than  a  milk  diet  will 
supply  it,  and  so  he  needs  starchy  foods,  like  bread, 
crackers,  and  other  cereals.  He  also  needs  less  milk 
when  he  begins  to  eat  solid  food.  In  fact,  we  ought  al- 
ways to  think  of  milk  as  a  food  and  not  as  a  drink  to  be 
used  in  the  place  of  water. 

Butter  contains  little  of  food  value  except  fat.  It  is 
made  by  separating  cream  from  milk  and  churning  the 
cream  until  the  butter  forms ;  this  leaves  a  liquid  called 
buttermilk. 

The  milk  from  which  the  cream  has  been  taken,  called 
skimmed  milk,  looks  blue  and  thin,  and  people  sometimes 
throw  it  away  thinking  that  it  has  no  food  value.  Cream 
looks  rich  and  strengthening;  but  the  fact  is  that  the 
cream  is  much  less  valuable  to  us  as  a  food  than  skimmed 
milk.  The  latter  has  just  as  much  of  building  food 
(protein)  as  before  it  was  skimmed  and  nearly  as  much 
sugar ;  what  it  has  lost  is  part  of  its  fat.  Those  who  want 
to  get  the  most  for  their  money,  by  buying  good  food  as 
cheaply  as  they  can,  ought  to  consider  how  they  can 
make  use  of  skimmed  milk,  which  is  really  both  cheap  and 
valuable. 

Another  form  in  which  we  use  milk  is  as  cheese.  Cheese 
is  made  from  the  curd  of  the  milk  by  separating,  pressing, 
and  preparing  it  in  various  ways.  There  is  great  food 
value  in  cheese  when  properly  used,  for  it  contains  all  the 
proteins  of  the  milk  and  most  of  the  fat. 


FOODS  WE  GET  FROM  ANIMALS         17 

Milk  Needs  Care.  —  If  we  all  lived  where  we  could 
have  our  own  cow,  keep  her  in  a  clean  barn,  and  milk 
her  twice  a  day,  with  spotlessly  clean  hands ;  if  we  could 
take  the  milk  to  a  clean  milk  room,  put  it  into  clean  pans, 
and  keep  it  there  at  the  right  temperature  until  time  for 
the  next  meal  —  then  there  would  be  no  necessity  for 
thinking  about  the  harm  that  may  come  from  unwhole- 
some milk.  Nor  would  there  be  as  many  sick  babies. 
But  most  of  us  have  to  get  our  milk  from  a  dealer. 
Dealers  and  milkmen  cannot  realize  how  much  sickness 
and  suffering  they  might  prevent  by  greater  care  in  han- 
dling milk ;  for  if  they  did,  they  would  certainly  be  more 
careful. 

When  milk  is  dirty,  we  cannot  see  the  dirt  as  we  see 
smuts  on  our  faces.  Occasionally  we  may  notice  some 
specks  in  it,  but  the  danger  comes  from  the  kind  of  dirt 
that  can  be  seen  only  with  the  microscope.  There  are 
various  disease  germs  that  may  easily  get  into  milk; 
some  float  in  the  air,  others  may  be  on  the  hands  of  the 
milkers,  or  in  the  utensils  used.  These  germs  are  too 
small  to  be  seen,  but  they  can  do  much  harm.  Milk 
may  carry  germs  that  cause  very  serious  diseases,  like 
typhoid  fever,  scarlet  fever,  and  tuberculosis  (consump- 
tion). Many  people  die  every  year  of  old  age,  but  more 
than  twice  as  many  die  from  the  results  of  drinking  dirty 
milk ;  and  it  produces  much  sickness  besides,  for  many 
of  the  illnesses  that  come  to  babies  and  young  children 
in  summer  are  caused  by  germs  in  the  milk  they  drink. 

What  can  we  do  about  it  ?  If  we  live  in  the  country, 
we  can  visit  the  dairy  from  which  our  milk  comes,  and 
see  whether  everything  possible  is  done  to  keep  the  milk 


18  PHYSIOLOGY   AND   HEALTH 

clean.  Then  we  can  make  sure  that  good  care  is  taken  of 
it  when  it  reaches  us.  As  soon  as  the  milk  is  delivered  it 
should  be  put  into  dishes  that  have  just  been  washed  in 
boiling  water  and  should  be  placed  immediately  in  an 
ice  chest  where  it  will  be  kept  cold  until  it  is  used. 

Why  Pasteurize  Milk.  —  Those  who  live  in  cities  can- 
not know  much  about  the  source  of  their  milk  supply, 
but  they  can  refuse  to  use  milk  until  it  has  been  made 
safe  by  a  very  simple  process,  called  pasteurization.  This 
consists  in  heating  the  milk  to  a  temperature  of  145°, 
allowing  it  to  stay  at  this  temperature  for  half  an  hour, 
and  then  cooling  it.  This  exact  amount  of  heat,  it  has 
been  found,  will  render  harmless  the  disease  germs  that 
may  be  in  the  milk,  without  injuring  the  milk  in  any  way, 
or  changing  its  taste. 

Some  cities  now  require  that  all  their  milk  (except 
Grade  A)  shall  be  pasteurized  before  it  is  sold,  thus  pro- 
tecting the  public  from  much  danger.  Cheap  milk  is 
always  poor  milk ;  it  is  likely  to  be  adulterated  with 
water,  which  can  easily  be  done  without  the  knowledge 
of  the  purchaser  and,  because  it  is  carelessly  handled, 
is  most  likely  to  contain  harmful  germs.  It  is  very 
dangerous  economy  to  buy  cheap  milk;  it  is  better  to 
pay  a  cent  or  two  more  a  quart  for  safe  milk  than  to 
buy  milk  dipped  out  of  a  big  can  that  is  kept  standing 
around  in  a  store,  and  then  pay  doctor's  bills  because 
the  milk  has  made  us  sick.  Milk  that  is  bottled  and 
sealed  before  it  is  shipped  is  much  safer. 

Meat.  —  All  kinds  of  meat  are  alike  in  one  respect :  they 
all  consist  of  lean  substance  (or  flesh),  some  fat,  and 
considerable  water.  It  is  the  protein  of  the  flesh  (find 


FOODS  WE  GET  FROM  ANIMALS 


19 


its  name  in  the  table  on  page  87)  that  makes  it  a  valuable 
building  food.  A  juicy  porterhouse  steak  may  suit  our 
taste  better  than  round  steak  or  a  piece  of  chuck  steak, 
but  the  cheaper  meats  are  as  nourishing  as  the  expensive 
cuts  ;  they  give  us  more  building  food  for  the  same  money. 
The  skill  of  the  cook  is  shown  by  her  ability  to  prepare 
the  cheaper  cuts  of  meat  so  well,  by  long  and  careful 
cooking,  that  we  shall  enjoy  them. 

Dangers  in  Meat.  —  Meat,  like  milk,  sometimes  con- 
tains hidden  dangers.  Spoiled  meat,  which  can  usually 
be  detected  by  its  color  and  odor, 
is  dangerous  because  of  the  poisons 

that  are  formed  in  it  as  it  spoils.     M   ,  _.. 

f  Nusde  Fibers- 

Vie  have  eyes  and  nose  to  help  us 

in  detecting  that  trouble,  espe- 
cially before  the  meat  is  cooked. 
But  there  are  other  troubles  that 
we  cannot  see  or  smell. 

In  the  flesh  of  pork,  even  when 
it  is  perfectly  fresh,  there  are  some- 
times tiny  worms,  called  Trichinae. 
They  are  too  tiny  to  be  seen  with- 
out a  microscope,  but  if  a  person 
swallows  them,  they  may  make  FIG.  6.  —  TRICHINA. 

him   Very   sick    Or    even    Cause    his    Showing  the  animal  in  a  bit 

death.     There  is  a  larger  worm,      of  muscle  tissue,  highly  mag- 

mfied. 

called  tapeworm,  that  is  sometimes 

found  in  both  pork  and  beef.  This  is  not  so  dangerous 
as  the  Trichina,  but  it  causes  discomfort  and  sometimes 
makes  one  ill.  When  meat  is  well  cooked,  there  is  no 
danger  from  tapeworm  or  Trichina. 


Trichina-- 


20  PHYSIOLOGY   AND   HEALTH 

Eggs.  —  When  the  chicken  hatches  out  of  its  shell,  it 
has  bones,  and  flesh,  and  fat.  Where  did  it  get  them? 
Evidently  the  materials  to  form  them  all  must  have  been 
in  the  egg,  for  the  chicken  has  had  nothing  else  on  which 
to  feed.  So  it  should  not  surprise  us  to  learn  that  eggs 
contain  protein  (albumen)  and  fat  as  well  as  a  little 
material  for  bone  making.  One  peculiar  thing  about  eggs 
is  that  we  get  the  greatest  food  value  from  them  when  we 
take  them  raw.  When  they  are  cooked,  the  albumen  in 
them  is  hardened,  which  makes  them  less  easy  for  the 
stomach  to  digest.  So  the  less  they  are  cooked  the  better ; 
and  the  harder  they  are  cooked  the  more  important  it  is 
that  we  should  chew  them  very  fine. 

QUESTIONS 

1.  Which  contains  the  more  protein,  meat    or  bread?      Which 
contains  the  more  carbohydrates  ?     How  do  peas  compare  with  meats 
in  these  respects?     Which  is  the  cheaper  food? 

2.  Can  you  give  any  reason  why  milk  is  the  best  food  for  babies? 
Why  is  it  not  an  equally  good  food  for  grown  people  ? 

3.  Does  skimmed  milk  contain  less  building  food  than  whole  milk? 
Does  it  contain  less  fuel  food?     Of  what  kind? 

4.  Describe  the  process  of  pasteurization. 

5.  Why  is  it  poor  economy  to  buy  cheap  milk? 

6.  Are  there  any  laws  in  force  in  your  state  or  community  in  re- 
gard to  the  care  and  distribution  of  milk?     Give  reasons  for  such  laws. 

7.  Why  are  raw  eggs  so  often  recommended  to  people  who  need 
to  be  "built  up"? 

8.  What  dangers  are  avoided  by  cooking  meat  ? 

9.  If  you  had  a  dollar  to  spend  for  a  meal  for  four  persons,  how 
could  you  spend  it  economically? 


CHAPTER   IV 
FOODS   WE   GET   FROM   PLANTS 

SOME  people  live  entirely  on  plant  food,  and  we  all 
get  the  greater  part  of  our  food  from  plants.  When  you 
sit  down  to  dinner  to-day,  notice  how  little  you  would 
have  to  eat  if  you  took  nothing  that  contained  any  of 
the  grains,  no  vegetables,  and  no  fruit. 

The  Grains,  or  Cereals.  -  -  This  country  raises  a  great 
many  cereals ;  enough  to  feed  our  own  people  and  to  sell 
millions  of  bushels  to  other  countries.  Our  principal 
cereals  are  wheat,  corn,  oats,  rice,  and  rye.  When  they 
are  ground  into  flour,  we  have :  from  wheat,  three  kinds 
of  flour  —  white,  whole-wheat,  graham;  from  corn,  corn- 
meal  (sometimes  called  Indian  meal) ;  from  oats,  oat- 
meal, and  from  rye,  rye  meal.  We  do  not  generally  use 
rice  in  flour  form,  but  in  some  countries  it  is  prepared 
in  that  way  as  well  as  in  a  number  of  others. 

All  cereals  contain  from  six  to  ten  times  as  much  fuel 
food  as  building  food.  Wheat  is  one  of  the  best  cereals 
for  constant  use,  since,  in  addition  to  starch  (fuel  food), 
it  contains  more  building  food,  gluten,  than  most  of  the 
others.  Under  the  microscope  the  starch  cells  and  the 
gluten  cells  look  entirely  different ;  Figure  7  shows  how 
the  microscope  sees  a  small  bit  of  a  grain  of  wheat, 
showing  both  the  starch  and  the  gluten  (protein)  cells. 
Wheat  and  gluten  look  just  as  different  from  each  other 

21 


22 


PHYSIOLOGY   AND    HEALTH 


Starch  holding  cells 


when  seen  in  oats ;  only  in  oats  there  is  a  larger  propor- 
tion of  gluten,  and  more  fat.  Do  you  see  why  people 
can  live  and  keep  well  on  a  diet  of  oatmeal  alone  ?  Rice 

contains  less  pro- 
tein and  less  fat 
than  wheat,  and 
more  starch.  Corn 
meal  is  richer  in 
fat  than  any  of 
the  other  cereals, 
except  oatmeal. 

Wheat  Flour.— 
If    you    were    to 
raise   wheat    and 
Protein  holding  cells   take  it  to  the  mill 

FIG.  7.  —  WHEAT  STARCH  AND  GLUTEN.  to  be  ground  into 

Showing  the  location  of  the   starch   and  the  gluten   flour,   WOUld    yOUT 

(protein)  cells  in  a  grain  of  wheat,  highly  magnified.     flQur  }ook  like  the 

white  flour  the  grocer  sells  ?  No,  it  would  be  darker  in 
color  and  coarser ;  the  bread  made  from  it  would  taste 
good,  but  it  would  look  dark,  somewhat  like  the  bread 
that  is  commonly  used  by  the  peasant  of  Europe.  It 
would  be  dark  because  it  would  contain  the  outer  husks 
of  the  wheat.  In  order  to  make  flour  as  white  as  possible, 
millers  have  found  an  ingenious  method  of  taking  wheat 
grains  to  pieces ;  they  remove  the  husks  and  grind  into 
flour  only  the  central  kernel  of  the  wheat.  Flour  so 
made  contains  nearly  all  the  gluten  in  the  grain ;  but  it 
has  lost  the  minerals  and  some  other  materials  necessary 
for  perfect  health  which  are  found  in  the  wheat  husk.  In 
making  graham  flour  and  whole-wheat  flour  the  husks 


FOODS  WE  GET  FROM  PLANTS         23 

are  ground  with  the  kernel,  and  so  these  flours  are  more 
valuable  and  healthful  than  white  flour. 

Beans  and  Peas.  —  The  cereals  are  the  most  valuable 
vegetable  foods.  Next  to  them  come  the  legumes  —  peas, 
beans,  and  peanuts,  which  are  really  a  kind  of  bean. 
They  are  excellent  substitutes  for  meat  and,  all  things 
considered,  are  more  valuable  than  meats.  A  larger 
amount  of  protein  is  contained  in  a  pound  of  beans  than 
in  a  pound  of  meat,  and  the  beans  are  much  cheaper. 
The  legumes  are  also  rich  in  starch.  People  who  live 
and  work  outdoors  thrive  on  them ;  those  who  lead  an 
inactive  life  sometimes  find  them  rather  hard  to  digest. 

Fruit  and  Vegetables.  —  If  the  common  foods  were 
listed,  putting  at  the  head  those  that  are  rich  in  protein, 
starch,  sugar,  or  fat,  most  of  the  vegetables  and  fruits 
would  appear  far  down  at  the  end  of  the  list !  Fruits 
contain  some  sugar  and  little  else  except  water;  most 
vegetables  are  seventy-five  to  ninety  per  cent  water.  We 
need  them  because  they  have  their  own  office  to  per- 
form :  they  stimulate  the  appetite ;  they  give  a  relish 
to  more  substantial  foods ;  they  help  to  keep  the  organs 
of  digestion  from  becoming  sluggish ;  and  then  they  do 
something  else  that  is  not  yet  really  understood,  even  by 
those  who  make  a  study  of  food.  Sailors  who  go  off  on 
long  voyages  find  that  unless  they  have  some  fresh 
vegetables  or  some  fruit  juices  they  are  likely  to  get  a 
disease  called  scurvy,  from  eating  nothing  but  canned  and 
cooked  food.  So  the  body  evidently  needs  something 
that  is  found  in  fresh  fruits  and  vegetables. 

There  are  some  vegetables,  like  potatoes,  parsnips, 
and  beets,  that  contain  enough  starch  or  sugar  or  pro- 


24  PHYSIOLOGY   AND   HEALTH 

tein  to  rank  as  foods  —  besides  serving  the  special  pur- 
poses mentioned  above.  Potatoes  contain  only  a  little 
protein ;  they  consist  largely  of  water  and  starch.  When 
we  eat  butter  on  them,  we  supply  fat ;  in  order  to  get  the 
necessary  proteins  with  them  we  should  eat  meat  or  milk 
or  cheese  or  one  of  the  legumes. 

Nuts.  —  Almonds,  walnuts,  and  peanuts  are  just  about 
as  rich  in  protein,  per  pound,  as  peas  and  beans.  The 
peas  and  beans,  we  have  learned,  also  have  much  starch. 
There  is  comparatively  little  starch  in  these  three  kinds 
of  nuts,  but  they  have  a  great  deal  of  fat.  Unfortunately 
nuts  are  hard  to  digest ;  for  that  reason  we  are  advised 
to  eat  sparingly  of  them  and  to  chew  them  very  fine. 

Foods  for  the  Brain  and  for  the  Bones.  —  Certain 
foods  are  widely  advertised  as  brain  foods.  They  will 
appeal  only  to  those  who  do  not  understand  that  the 
brain  needs  exactly  the  same  food  as  the  muscles  and  the 
other  parts  of  the  body.  Any  food  that  nourishes  the 
rest  of  the  body  will  feed  the  brain ;  there  is  no  need  of 
buying  any  special  food  for  it.  The  so-called  "  brain 
foods  "  are  usually  much  more  expensive,  but  not  more 
valuable,  than  oatmeal  or  cracked  wheat. 

Nature  has  also  made  adequate  provision  for  material 
to  build  the  bones.  Part  of  the  bone  is  made  of  protein, 
which  we  eat  in  some  form  every  day ;  the  mineral  matter 
of  the  bone  is  lime,  and  there  is  a  sufficient  quantity  of 
lime  in  our  common  foods,  such  as  meat,  bread,  milk, 
and  eggs.  So  the  child  who  eats  these  common  foods 
gets  all  the  bone-making  material  that  he  needs.  He 
will  get  little  "bone  food"  from  cake  and  none  from 
candy. 


FOODS  WE   GET   FROM  PLANTS  25 


QUESTIONS 

1.  What  countries  use  rice  as  the  chief  article  of  diet? 

2.  What  cereals  are  most  used  in  this  country? 

3.  From  a  study  of  the  table  on  page  87,  would  you  think  that 
wheat  or  oatmeal  would  be  the  better  cereal  to  use  alone  as  an  article 
of  diet?     Why? 

4.  Why  is  graham  flour  a  more  valuable  food  than  white  flour? 
Which  contains  the  more  protein? 

5.  Why  can  beans  be  used  as  a  substitute  for  meat?    Can  you 
think  of  any  objections  to  using  them? 

6.  Can  you  think  of  any  good  reason  why  meat  and  potatoes  go 
well  together  as  a  meal? 

7.  Which  would  be  the  better  to  use  together  at  a  meal,  potatoes 
and  rice  or  potatoes  and  beans  ?    Why  ? 

8.  What  kind  of  food  should  we  eat  for  brain  food?    What  kind 
to  build  bones? 

9.  Make  out  a  menu  for  what  seems  to  you  a  well-balanced  meal 
which  shall  consist  wholly  of  plant  foods. 

10.  What  mistakes  do  people  often  make  in  selecting  the  different 
articles  of  food  which  go  to  make  up  a  meal  ? 

11.  Will  a  diet  of  fruit  and  vegetables  furnish  the  body  with  all  it 
needs?    Give  reasons  for  your  answer. 

12.  How  do  the  following  materials   compare  as  focds:   celery, 
lettuce,  peanuts,  apples,  cheese,  bacon,  olive  oil,  potatoes,  peas? 

13.  Why  is  macaroni  and  cheese  a  nourishing  dish? 

14.  Name  all  the  kinds  of  sandwiches  you  can  think  of.    Which 
are  the  most  nourishing  for  you  to  bring  for  lunch  ? 

15.  Make  out  a  list  of  the  best  foods  to  take  with  you  on  a  week's 
camping  trip. 


CHAPTER  V 
THE  PURCHASE  AND   CARE   OF  FOOD 

Doing  the  Marketing.  —  Every  one  should  know  how 
to  buy  food,  and  how  to  take  care  of  it.  To  do  the 
"  marketing  "  properly  requires  study  and  much  care. 
Think  of  the  amount  of  money  that  the  people  of  the 
United  States  spend  for  food  every  year :  about  $15,000,- 
000,000.  Ought  it  not  to  be  expected  that  those  who  have 
the  spending  of  all  that  money  shall  know  how  to  get 
full  value  for  it  ? 

Some  people  think  that  if  they  pay  the  highest  price 
for  everything  they  are  sure  to  get  the  best ;  that  is  a 
great  mistake.  The  most  expensive  cuts  of  meat  are 
no  better  foods  than  the  cheaper  cuts.  Skimmed  milk 
is  one  of  the  best  foods  and  one  of  the  cheapest.  When 
it  comes  to  the  selection  of  fruits  and  vegetables,  most  of 
them  have  their  "  season  "  when  they  are  at  their  best, 
and  being  most  plentiful,  are  also  cheapest.  Since  grapes 
are  cheapest  (and  best)  in  October,  would  that  not  be  a 
foolish  time  to  buy  oranges,  which  are  just  beginning 
to  come  into  the  market,  and  so  are  very  high?  What 
about  buying  grapes  in  January,  when  the  oranges  are 
at  their  best?  In  some  markets  eggs  are  separated  ac- 
cording to  the  color  of  their  shells.  If  strictly  fresh 
brown  eggs  were  selling  at  30  cents  a  dozen,  and  strictly 
fresh  white  eggs  at  40  cents  a  dozen,  would  it  be  sensible 
to  pay  the  extra  10  cents  for  those  with  the  white  shells  ? 

26 


THE  PURCHASE  AND  CARE  OF  FOOD       27 

Impure  and  Adulterated  Foods.  —  We  buy  some  foods 
after  they  have  been  cooked  or  prepared  ;  it  is  then  more 
difficult  to  tell  whether  they  are  pure.  There  is  always 
a  demand  for  "  cheap  goods/'  even  when  it  comes  to 
foods.  Some  dealers  meet  this  demand  by  adulterating 
their  foods  —  to  adulterate  a  food  means  to  mix  with  it 
some  substance  that  seems  like  it  but  is  less  expensive. 
The  added  substance  is  not  always  healthful ;  sometimes 
it  is  one  that  we  should  not  be  willing  to  eat  if  we  knew 
what  it  was;  sometimes  it  is  harmless,  but  has  no  real 
food  yalue. 

Adulterated  Foods  are  Expensive.  —  If  the  best  coffee 
was  25  cents  a  pound,  would  you  be  gaining  or  losing  if 
you  bought  a  can  of  ground  coffee  at  20  cents  which  was 
f  good  coffee  and  J  ground  beans?  You  would  get  no 
food  value  from  the  beans  (coffee  is  not  cooked  long 
enough  to  cook  beans),  and  besides  they  would  spoil 
the  flavor  of  the  coffee.  Or  suppose  you  were  given 
granulated  (cane)  sugar  that  was  adulterated  with  glu- 
cose. The  sugar  would  not  be  so  sweet,  and  you  would 
find  that  you  had  to  use  more  of  it  to  get  the  same  result  ; 
then  the  sugar  would  really  cost  you  more  than  if  you 
paid  more  but  bought  pure  sugar.  Or  you  might  buy 
milk  that  had  been  adulterated  by  mixing  it  with  water ; 
pure  water  is  harmless,  but  it  comes  high  at  the  price  of 
milk,  6  or  8  cents  a  quart.  Honey  is  adulterated  with 
glucose ;  chocolate  is  adulterated  with  starch ;  pepper 
is  mixed  with  flour,  charcoal,  and  sawdust ;  it  is  even 
possible  to  make  delicious-looking  and  palatable  jellies 
and  jams  from  apple  cores,  by  using  coloring  matter  and 
flavoring. 


28  PHYSIOLOGY   AND   HEALTH 

Some  Rules  for  Buying.  —  Those  who  buy  food  should 
remember : 

1.  The  cheaper  'grades  of  cooked  or  prepared  foods 
are  more  likely  to  be  adulterated  than  the  better  grades. 

2.  Canned    foods    are    easily    adulterated,    especially 
minced  meats  or  anything  else  that  is  cut  up  fine.     Cheap 
grades  of  canned  goods  are  very  likely  to  be  adulterated 
with  some  cheap  and  usually  worthless  material. 

3.  Adulterated  canned  goods  are  really  more  expensive 
than  the  better  grade  of  goods,  because  they  give  less 
food  value. 

Spoiled  Foods.  —  Many  dried  foods  may  be  kept  in 
good  condition  for  a  long  time,  but  moist  foods  are  sure 
to  "  spoil "  if  they  are  not  given  proper  care.  The  way 
to  take  care  of  them  is  to  protect  them  from  the  bacteria 
in  the  air.  These  tiny  plants  are  always  present  in  the 
air,  outdoors  and  indoors.  When  they  get  into  moist 
food,  they  begin  to  feed  on  it,  and  then  they  multiply 
very  rapidly.  Soon  they  produce  disagreeable  changes  in 
the  food,  which  we  call  molding,  or  putrefying.  Putre- 
fied or  decayed  food  is  not  only  unpleasant  to  taste  and 
to  smell,  but  it  is  actually  dangerous,  because  the  bacteria 
that  grow  in  it  sometimes  produce  deadly  poisons,  called 
ptomaines.  Those  who  eat  food  in  which  ptomaines  have 
been  formed  are  likely  to  become  violently  ill  within  a 
very  short  time. 

Ptomaine  poisoning  is  characterized  by  vomiting  and 
diarrhea  —  which  result  from  the  effort  the  body  makes 
to  get  rid  of  the  deadly  poison  as  quickly  as  possible. 
Spoiled  fish,  cheese,  ice  cream,  and  meat  are  the  most 
frequent  causes  of  ptomaine  poisoning.  It  is  not  possible 


THE  PURCHASE  AND  CARE  OF  FOOD       29 

to  detect  the  presence  of  these  poisons  in  food,  either  by 
smell  or  by  taste ;  but  at  least  we  can  make  it  a  rule  not 
to  eat  any  food  that  we  have  reason  to  fear  may  be  spoiled. 

Importance  of  an  Ice  Box.  —  There  are  so  many 
bacteria  in  the  air  that  it  is  almost  impossible  to  keep 
them  out  of  food  ;  we  can,  however,  prevent  their  harm- 
ing it.  The  best  way  to  prevent  their  injuring  our  food 
is  to  keep  the  food  very  cold.  In  summer,  milk,  butter, 
meat,  fish,  and  all  moist  food,  cooked  or  uncooked,  should 
be  put  into  the  ice  box  just  as  soon  as  they  are  taken  from 
the  table  —  no  standing  in  a  warm  kitchen  or  pantry  un- 
til it  is  "  convenient "  to  put  them  into  the  ice  box.  Even 
in  winter  it  is  not  safe  to  keep  them  where  it  is  warm. 
This  is  particularly  true  of  milk,  which  in  warm  weather 
gets  unwholesome  after  a  few  hours  in  the  open  air,  but 
may  be  kept  much  longer  in  an  ice  box. 

If  a  household  has  no  ice  box,  the  only  safe  plan  in  hot 
weather  is  to  purchase  in  small  quantities  such  food  as  is 
likely  to  spoil,  securing  it  from  a  reliable  dealer  who  keeps 
it  well  iced ;  then  have  it  eaten  immediately,  before  it 
has  a  chance  to  spoil. 

Cold-storage  Food.  —  Most  large  cities  have  cold-storage 
warehouses.  In  these  immense  buildings  food  is  packed 
away  at  the  season  when  it  is  abundant  for  use  at  the 
season  when  it  is  scarce.  The  temperature  in  them  is 
kept  down  almost  to  freezing,  and  sometimes  below  that 
point,  thus  preserving  the  food  as  long  as  it  remains  in 
the  warehouse.  Dealers  who  handle  cold-storage  food 
are  obliged,  in  many  cities,  to  hang  up  a  sign  stating  that 
fact,  and  to  tell  customers  what  they  are  buying.  That 
is  not  because  cold-storage  food  is  necessarily  unwhole- 


30  PHYSIOLOGY   AND   HEALTH 

some,  but  because  it  must  be  eaten  at  once,  for  it  is  likely 
to  spoil  very  quickly. 

Preservatives.  —  In  order  to  keep  their  food  from  spoil- 
ing, manufacturers  sometimes  put  into  it  certain  chemical 
substances  called  preservatives.  This  is  especially  true 
of  sauces,  catsups,  and  other  foods  likely  to  be  exposed 
to  the  air.  For  sauces,  benzoic  acid  is  commonly  used, 
and  for  other  foods  borax,  salicylic  acid,  and  formalin 
are  employed.  These  are  all  poisons,  as  is  shown  by  the 
fact  that  they  kill  bacteria  or  keep  them  from  growing; 
to  be  sure  they  are  mild  poisons  but  they  are  harmful  in 
foods.  Another  way  in  which  some  of  these  preservatives 
are  used  is  in  meat  that  is  beginning  to  decay  (and  for 
this  reason  is  cheap) ;  their  use  prevents  the  offensive 
tastes  that  would  warn  the  consumer  that  the  meat  is 
unfit  for  food.  Sauces,  meats,  fish,  milk,  and  canned 
goods  are  most  commonly  preserved  in  this  way.  The 
cheaper  grades  are  always  the  ones  most  likely  to  be 
"  preserved." 

Pure  Food  Laws.  —  It  is  quite  impossible  for  each  in- 
dividual in  our  communities  to  make  sure  that  the  food 
he  buys  is  pure  and  wholesome.  We  have  to  buy  what 
is  in  the  market.  Our  food  comes  from  such  distances 
that  in  many  cases  it  is  quite  impossible  for  us  to  know 
anything  about  its  source.  The  protection  of  food 
becomes,  therefore,  a  public  duty  which  must  be  con- 
trolled by  laws.  The  government  has  passed  pure  food 
laws  that  make  it  a  crime  to  adulterate  food,  or  to  treat 
it  with  preservatives,  or  to  label  it  improperly.  But  the 
enforcement  of  these  laws  has  to  be  left  to  public  officials. 
Food  inspectors  of  various  kinds  are  always  on  the  look- 


THE  PURCHASE  AND  CARE  OF  FOOD       31 

out  to  prevent  the  public  from  being  cheated  by  adulter- 
ated foods,  or  poisoned  by  spoiled  and  "  preserved  "  foods. 
Cities  also  commonly  supervise  very  carefully  the 
conditions  under  which  vegetables  and  fruits  are  offered 
for  sale,  since  these  foods  are  unwholesome  when  they 
are  overripe  or  when  they  are  exposed  to  the  danger  of 
harboring  germs.  Those  who  offer  them  for  sale  are 
frequently  required  to  keep  them  covered,  in  order  to 
prevent  their  being  powdered  with  dust  or  visited  by 
insects  that  might  dangerously  contaminate  them. 

QUESTIONS 

1.  What  are  some  of  the  ways  in  which  one  can  economize  in 
marketing  without  loss  or  danger  to  oneself? 

2.  In  the  purchase  of  what  kinds  of  foods  is  economy  unwise? 

3.  Name  some  foods  that  are  often  adulterated  and  describe  how 
this  is  done. 

4.  What  causes  meat  to  spoil  if  it  is  left  in  the  air?    How  can  you 
tell  when  it  is  spoiled  ?    What  can  you  do  to  make  the  meat  keep  better  ? 

5.  Name  some  of  the  chemicals  that  are  often  used  as  "  preserva- 
tives."     Why  do  manufacturers  find  it  to  their  advantage  to  treat 
food  in  this  way? 

6.  What  is  the  cause  of  ptomaine  poisoning? 

7.  Why  do  we  need  an  ice  box  in  the  home? 

8.  Tell  what  you  know  about  the  care  of  a  refrigerator. 

9.  Which  is  likely  to  be  the  better  way  to  obtain  good  meat  and 
vegetables  —  to  go  to  the  market  or  to  order  by  telephone  ? 

10.  Find  out  what  measures  have  been  taken  in. your  community 
to  lessen  the  danger  to  the  public  from  spoiled  or  " preserved"  foods. 

11.  Find  out,  if  you  can,  which  are  the  safest  brands  of  canned  or 
bottled  foods. 

12.  How  soon  after  a  can  is  opened  should  the  contents  be  used? 

13.  Find  out  from  the  health  department  of  your  town  or  city  what 
is  the  grade  of  the  milk  which  you  are  drinking. 


CHAPTER  VI 
BEVERAGES 

Water.  —  It  is  ^ell  known  that  men  can  live  without 
food  much  longer  than  they  can  live  without  water.  Yet 
a  great  many  persons  who  have  both  at  hand,  in  abun- 
dance, eat  too  much  food  and  drink  too  little  water.  There 
is  little  danger  of  drinking  too  much  water  unless  we 
drink  it  too  cold  or  at  the  wrong  time.  The  worst  time 
to  drink  it  is  when  we  are  chewing  our  food.  The  ex- 
pression "  washing  down  the  food  "  describes  how  water 
should  never  be  used.  We  know  that  we  cannot  swallow 
dry  food  until  it  has  been  moistened,  but  nature  has 
provided  the  way  to  moisten  it,  that  is,  with  the  saliva. 
When  we  drink  water  to  moisten  the  food,  we  defeat 
nature's  plans,  which  always  means  that  we  make  trouble 
for  ourselves. 

Impurities  in  Water.  —  We  have  learned  that  the  worst 
dangers  in  milk  are  the  invisible  ones ;  and  that  is  also 
true  of  water.  It  may  look  clear  and  taste  pure,  and  yet 
be  unsafe  to  drink  because  of  minute  bacteria  contained 
in  it.  Some  of  these  are  harmless,  and  some,  when  taken 
into  the  body,  produce  disease.  So  we  need  to  know, 
as  in  the  case  of  milk,  where  our  drinking  water  comes 
from,  and  whether  it  reaches  us  as  clean  as  it  was  at  the 
start. 

Water  from  a  deep  spring  is  almost  always  pure,  unless 

32 


BEVERAGES 


33 


the  spring  is  near  some  foul  place,  like  an  open  drain  or 
barnyard.  Wells,  however,  are  so  easily  contaminated 
that  they  need  to  be  carefully  protected.  There  have 
been  instances  in  which  many  cases  of  typhoid  fever 
were  directly  traced  to  a  single  contaminated  well.  In 
the  country  a  man  can  guard  his  own  well  or  spring  if  he 


FIG.  8.  —  A  PROPERLY  LOCATED  AND  CONSTRUCTED  WELL. 

will  only  give  his  attention  to  it.  He  should  remember 
that  the  greatest  danger  comes  from  allowing  the  ex- 
cretions of  men  or  animals  to  pollute  it.  There  is  little 
chance  for  pollution  if  the  well  is  on  ground  higher  than  the 
location  of  the  house  and  barn.  Figure  8  shows  a  properly 
located  and  constructed  well.  A  well  like  that  shown  in 


34  PHYSIOLOGY   AND   HEALTH 

Figure  9,  which  is  lower  than  the  house,  may  easily  be- 
come contaminated,  and  hence  it  is  a  constant  source  of 
danger  to  those  drinking  from  it. 

The  most  dangerous  source  of  water  supply  is  a  river, 
for  most  rivers  receive  sewage  from  the  cities  and  towns 


FIG.  9.  —  AN  IMPROPERLY  LOCATED  AND  CONSTRUCTED  WELL. 

on  their  banks.     Many  towns   feel   that   they  have   a 
perfect  right  to  empty  their  sewage  into  the  river. 

In  towns  and  cities  people  cannot  have  their  own  springs 
and  wells ;  they  are  dependent  upon  the  water  the  city 
supplies.  Often  they  know  nothing  about  its  source, 


BEVERAGES  35 

and  there  is  nothing  they  could  do  to  keep  it  from  being 
contaminated.  So  cities  and  towns  have  to  be  responsible 
for  taking  care  of  their  water  supply ;  how  they  do  this  is 
explained  in  Section  IV,  Chapter  I. 

Other  Beverages.  -  -  Young  people  are  much  better 
off  without  either  tea  or  coffee.  How  much  harm  these 
beverages  may  do  no  one  really  knows,  but  it  is  agreed 
that  they  do  no  good,  have  no  food  value,  and  in  some 
cases  are  actually  injurious.  Cocoa  and  chocolate,  on  the 
other  hand,  are  good  drinks  for  young  people,  especially 
if  they  are  not  made  too  .strong.  At  soda  fountains 
Americans  consume  large  quantities  of  "  soft  drinks  " ; 
these  quench  thirst  only  because  of  the  water  in  them.  It 
is  an  expensive  way  of  buying  water ;  yet  such  beverages 
do  no  special  harm  unless  one  takes  them  too  frequently, 
and  then  the  sirups  in  them  may  prove  injurious. 

Alcohol. -- There  is  one  class  of  beverages  which  is 
always  harmful  and  never  beneficial ;  that  is  the  class 
of  alcoholic  beverages.  In  the  middle  of  the  last  century 
there  were  many  intelligent  people  who  thought  that 
alcohol,  in  some  of  its  forms,  was  good  for  them.  They 
knew  that  it  was  made  from  fruits  or  from  grains,  and 
they  thought  it  must  have  in  it  all  the  "  goodness  "  of 
the  grain  or  the  fruit.  So  they  imagined  that  it  was  good 
for  them  and  for  their  children. 

But  doctors  found  that  persons  who  used  alcohol  were 
not  so  strong,  not  so  well  able  to  resist  disease  as  those 
who  did  not  use  it.  Railroad  companies  discovered  that 
the  lives  of  their  passengers  were  not  safe  in  the  hands 
of  employees  who  took  any  form  of  alcoholic  drink ;  so 
people  began  to  realize  that  much  mischief  lies  concealed 


36  PHYSIOLOGY   AND   HEALTH 

in  alcohol.     Then  all  over  the  world,  in  different  hospitals 

and  laboratories,  men  began  to  study  the  nature  and  effects 

of  alcohol. 

The  Alcohol  Makers.  —  Men  knew  long  ago  that  if 

they  did  certain  things  to  grains  or  fruits,  alcohol  would 

be  produced ;  why  it  could  be 
made  in  those  ways  only  they  did 
not  know.  Finally  scientists  dis- 
covered that  alcohol  never  was 
produced  without  the  presence 
FIG.  10.  —  YEAST  CELLS.  of  certain  very  tiny  little  plants, 

The  ceils  on  the  left  are  very  which  can  be  seen  only  with  the 

highly  magnified ;  those  on  the         .  rr,-,  -, 

right  less  magnified,  but  ar-  microscope.      These   plants  are 

ranged  to  show  clusters  formed  sometimes     called    yeasts     and 

by  budding.  sometimes       called       ferments. 

When  they  get  into  fruit  juices  or  into  sweet  liquids 

made  from  grain,  they  at  once  set  to  work  on  them. 

When  the  yeasts  are  through  their  work,  they  have  so 
changed  the  nature  of  the  juices  that  none  of  the  goodness 
of  the  grain  or  the  fruit  is  left.  How  do  they  do  it? 
Just  by  feeding  themselves.  They  are  very  fond  of 
sweet  juices.  So  when  they  have  a  chance,  they  feed  on 
them ;  then  they  grow  very  rapidly.  As  they  grow  they 
change  the  nature  of  the  juice ;  bubbles  of  gas  begin  to 
rise  to  the  top  of  the  liquid,  and  at  the  same  time  alcohol 
is  produced.  The  gas  passes  off  into  the  air,  but  the  al- 
cohol stays  in  the  liquid.  The  pure  grape  juice  has  been 
changed  into  a  dangerous  drink  by  the  alcohol  that  has 
formed  in  it. 

When  Ferments  Are  Harmless.  —  Where  do  these 
sugar-loving  ferments  come  from?  Are  they  dangerous 


BEVERAGES  37 

to  us  like  some  of  the  bacteria  that  get  into  water?  No, 
they  are  commonly  quite  harmless ;  in  fact  they  are 
floating  about  in  the  air  much  of  the  time.  They  are 
on  the  skin  of  fruits,  and  you  can  even  buy  them  from  the 
grocer.  Only  you  must  ask  him  for  yeast ;  and  when  he 
gives  you  a  two-cent  cake  of  compressed  yeast,  you  are 
buying  millions  of  these  tiny  plants. 

Yeast  plants  are  used  to  raise  bread. 

They  act  upon  the  bread  dough  just  as  they  did  upon 
the  fruit  juices.  But  the  bread  is  not  sweet  enough  to 
suit  them;  so  they  only  make  a  tiny  bit  of  alcohol 
which  is  driven  out  of  the  bread  by  the  heat  of  the  oven. 
In  bread,  particularly  in  whole-wheat  bread,  we  get  all 
the  good  of  the  wheat ;  in  alcoholic  drinks,  made  from 
grain,  we  lose  the  good  of  the  grain  and  make  a  bad  ex- 
change, for  we  get  in  its  place  a  new  and  harmful  sub- 
stance, alcohol. 

Fermented  Liquors.  —  Even  the  ferments  cannot  thrive 
and  go  on  growing  in  the  alcohol  that  they  make ;  when 
they  have  made  a  certain  percentage  of  alcohol,  they  have 
to  stop  work.  The  beverages  that  they  make  are  named 
after  them,  fermented  liquors.  The  most  common  of  the 
fermented  liquors  are : 

Beer  and  ale,  made  from  grains,  and  containing  from 
3  per  cent  to  8  per  cent  of  alcohol. 

Wine,  made  from  fruit  juices,  and  containing  from  9 
per  cent  to  15  per  cent  of  alcohol. 

Cider,  made  from  apples,  and  containing  according  to 
its  age  from  2  per  cent  to  30  per  cent  of  alcohol;  cider 
is  really  an  apple  wine. 

Distilled  Liquors.  —  There  is  a  special  process,  called 


38  PHYSIOLOGY   AND   HEALTH 

distilling,  by  which  liquors  are  made  stronger  (in  alcohol) 
than  the  ferments  will  make  them.  In  this  process  part 
of  the  water  that  is  in  the  liquid  is  removed ;  then  there 
is,  of  course,  a  larger  percentage  of  alcohol  than  before. 
Distilled  liquors  contain  from  25  per  cent  to  55  per  cent 
of  alcohol.  The  rest  of  the  liquor  is  water  with  a  little 


Cider  Beer  Wine  Whisky          Brandy 

FIG.  11.  —  RELATIVE  AMOUNTS  OP  ALCOHOL. 
The  figure  shows  the  relative  amounts  of  alcohol  in  different 
alcoholic    beverages.     The    dark    portion    represents    the 
alcohol,  the  rest  being  mostly  water. 

flavoring  matter ;  the  water  is  the  only  useful  thing  in  it, 
since  the  alcohol  is  harmful.  The  most  common  distilled 
liquors  are  rum,  whisky,  gin,  and  brandy  (see  Figure  11). 
Notice  how  large  is  the  amount  of  alcohol  in  such  liquors 
as  whisky  and  brandy. 

There  is  nothing  in  any  one  of  these  beverages  that 


BEVERAGES  39 

makes  them  necessary  or  even  desirable  for  a  person  in 
good  health  and  much  that  makes  them  dangerous.  To- 
day many  doctors  believe  they  are  of  no  use,  even  in 
illness ;  when  used,  they  should  be  carefully  prescribed, 
just  like  other  drugs.  The  boy  or  girl  who  wishes  to  be 
vigorous,  useful,  and  successful  should  let  them  absolutely 
alone. 

The  Alcoholic  Appetite.  —  All  physicians  know  that 
persons  "  respond  "  differently  to  the  same  kind  of  medi- 
cine. Some  can  take  twice  as  much  of  a  drug  as  others 
without  its  affecting  them;  and  nobody,  not  even  the 
doctor,  can  tell  to  which  class  he  belongs.  It  is  the  same 
with  alcohol.  Some  people  can  go  along,  year  after  year, 
drinking  such  small  amounts  that  the  alcohol  does  not 
seem  to  do  them  much  harm.  Others  are  quite  unable 
to  do  this,  for  as  soon  as  they  take  a  little,  they  have 
a  craving  that  cannot  be  satisfied  except  with  more  and 
more  alcohol.  But  even  those  of  the  first  class  are  never 
safe:  they  are  really  injured  by  the  habit  and  too  often 
they  wake  up  some  day  to  find  that  without  realizing  it 
they  have  formed  a  desire  for  alcohol  that  they  cannot 
shake  off. 

The  fact  is  that  the  use  of  alcohol  creates  a  diseased 
appetite ;  its  effect  on  the  body  is  such  that  by  and  by 
the  man  is  uncomfortable  without  alcohol  —  and  all  the 
time  it  takes  more  and  more  of  it  to  satisfy  him.  A  person 
may  be  very  strong  and  may  at  first  seem  to  be  able  to 
resist  any  bad  appetite  ;  but  this  does  not  give  him  protec- 
tion ;  for  all  the  time  the  alcohol  is  undermining  his 
strength.  No  one  is  really  safe  from  this  danger  except 
the  one  who  never  begins  to  use  alcoholic  drinks. 


40  PHYSIOLOGY  AND   HEALTH 


QUESTIONS 

1.  Why  should  we  not  wash  food  down  with  water?    Does  this 
mean  that  we  should  not  drink  water  during  the  meals  ? 

2.  When  a  person  experiences  difficulty  in  swallowing  his  food 
without  taking  water  or  some  other  liquid  with  it,  what  is  the  reason  ? 

3.  How  many  glasses  of  water  do  you  drink  in  a  day?     When  do 
you  drink  them  ? 

4.  Can  you  think  of  any  reason  why  cocoa  and  chocolate  are  good 
for  children  while  tea  and  coffee  are  not? 

5.  What  is  the  source  of  the  water  that  you  use  at  your  home? 
Who  guards  it  from  contamination?     Is  it  pure?    What  would  you 
do  if  you  suspected  it  to  be  dangerous  to  drink? 

6.  Why  did  people  formerly  think  that  alcohol  was  good  for  them? 

7.  What  will  yeast  do  to  fruit  juices? 

8.  Hard  cider  is  sweet  apple  juice  that  has  been  fermented  by 
yeast  plants.     Where  was  this  yeast  before  the  apples  were  ground  ? 

9.  If  yeast  is  grown  in  bread  dough,  why  is  bread  not  harmful  like 
beer? 

10.  Which  are  the  more  dangerous  drinks,  fermented  or  distilled 
liquors?    Why? 

11.  Can  you  think  of  any  good  reason  why  a  person  should  use  an 
alcoholic  drink  ?     Can  you  think  of  reasons  why  he  should  not  ?     What 
are  they? 

12.  What  is  meant  by  the  alcohol  appetite?    How  is  it  acquired? 

13.  Does  alcohol  quench  thirst? 

To  THE  TEACHER.  Bring  a  little  fresh  fruit  juice  into  class.  Let 
pupils  taste  it.  Then  let  it  stand  in  the  room  uncovered  for  a  few 
days  and  ask  pupils  to  taste  it  again,  likewise  observing  the  changes 
in  its  appearance. 

Into  a  small  vial  pour  a  solution  of  molasses  and  water.  Add  to  it  a 
few  drops  of  yeast  (made  by  dissolving  a  small  piece  of  compressed 
yeast  in  water)  and  let  it  stand  in  a  warm  place  for  about  twenty-four 
hours.  Then  have  pupils  observe  changes  which  have  taken  place. 


CHAPTER  VII 
THE   FIRST   STEP   IN   DIGESTION 

Digestion.  —  The  food  we  buy  must  be  greatly  changed 
before  it  can  be  taken  up  by  the  body  as  nourishment. 
Cooking  makes  some  changes,  but  these  changes  are 
slight  compared  with  those  that  take  place  in  the.  cooked 
food  after  we  have  eaten  it.  The  blood  is  the  food 
carrier,  and,  since  it  will  not  carry  solid  bits  of  food,  the 
bread,  the  meat,  and  the  potato  that  we  eat  must  be 
liquefied  before  they  can  be  carried  over  the  body.  The 
process  by  which  food,  after  being  eaten,  is  so  changed 
that  it  can  be  taken  into  the  blood  is  called  digestion. 

The  process  of  digestion  begins  in  the  mouth  and 
ends  in  the  large  intestine  (see  Figure  18).  At  first  it  is 
partly  under  our  control ;  that  is,  we  can  do  as  we  like 
about  a  certain  part  of  the  process.  The  other  parts 
of  it  are  not  under  the  control  of  the  will.  If  the  part 
we  control  is  well  done,  the  other  parts  will  be  done  well 
too. 

Digestion  as  Team  Work.  —  Digestion  is  an  excellent 
example  of  team  work.  Let  us  say  that  a  boy  begins 
the  play  when  he  sits  down  to  the  breakfast  table  and 
begins  to  eat.  Before  long,  he  passes  the  play  to  others ; 
that  is,  to  parts  of  his  body  which  know  their  share  of 
the  game  and  do  not  have  to  be  told  what  to  do.  He  is 
the  only  player  on  the  team  who  needs  coaching ;  and 

41 


42 


PHYSIOLOGY  AND   HEALTH 


FIG.  12. — A  VERTICAL  SECTION 

THROUGH    THE    BODY. 

The  location  of  the  important 
organs  is  shown.  Ht,  heart; 
In,  intestine;  Li,  liver;  Lu, 
lung;  Sp.c,  spinal  cord;  St, 
stomach. 


he  is  likely  to  interfere  with  the 
work  of  the  others,  for  he  cannot 
see  what  they  have  to  do  or  how 
they  do  it.  In  fact,  the  whole 
process  of  digestion  was  a  mys- 
tery for  many  centuries.  One 
part  of  the  process  was  dis- 
covered and  then  another ;  when- 
ever a  physician  had  a  patient 
whose  digestive  organs  were 
markedly  abnormal,  that  case 
was  carefully  studied  and  the 
conclusions  drawn  from  it  were 
given  to  other  students.  So, 
little  by  little,  many  marvels  of 
the  digestive  process  have  been 
found  out ;  other  parts  are  not 
yet  fully  understood. 

What  Chewing  Does  for  the 
Food.  —  Dr.  Horace  Fletcher 
was  much  interested  in  food  and 
made  many  experiments  upon 
himself.  He  found  that  when 
he  chewed  his  food  a  long  time, 
he  was  satisfied  with  less  to  eat, 
and  he  concluded  that  long  chew- 
ing enabled  him  to  make  better 
use  of  what  he  ate.  However 
that  may  be,  all  doctors  are 
agreed  that  our  food  should  be 
thoroughly  chewed  before  it  is 


THE  FIRST  STEP  IN  DIGESTION 


43 


swallowed.  The  stomach  works  only  on  the  outside  of 
the  pieces  of  food  we  give  it.  When  we  chew  a  piece  of 
bread  until  it  is  divided  into  hundreds  of  little  bits,  then 
the  stomach  has  hundreds  of  pieces  on  which  to  set  to 
work.  It  can  do  its  work  much  faster  and  easier  that 
way  than  when  we  give 
it  a  few  big  lumps.  If  a 
person  is  in  a  hurry  and 
does  not  chew  his  food 
well,  then  the  stomach 
has  to  try  to  make  .up  for 
his  carelessness  by  work- 
ing harder  than  it  should. 
The  result  is  the  same  as 
when  one  member  of  a 
team  fails  to  do  his  work 
properly. 

Solid  food  ought  not  to 
be  swallowed  until  it  is 
ground  into  a  fine  pulp.  While  that  preparatory  grinding 
is  going  on,  something  else  is  also  taking  place,  which 
forms  the  first  step  in  digestion. 

Saliva  Starts  the  Digestion  of  Starch.  —  When  we 
begin  to  eat,  our  mouths  become  moist  with  a  fluid  called 
saliva.  This  is  produced  by  three  pairs  of  glands ;  two  of 
them  are  under  the  tongue  and  another  pair  on  the  sides 
of  the  face  in  front  of  the  ear  (see  Figure  13).  All  of 
these  glands  have  openings  into  the  mouth.  They  are 
most  active  while  we  are  eating;  sometimes  even  the 
sight  of  food  sets  them  to  doing  extra  work.  When 
we  say  that  the  thought  of  food  "  makes  the  mouth 


GlaJids 


FIG.  13.  —  THE  SALIVARY  GLANDS. 


44  PHYSIOLOGY   AND   HEALTH 

water,"  we  are  saying  that  it  makes  the  salivary  glands 
active.  Every  day  they  produce  about  a  quart  of  saliva ; 
most  of  it  is  used  to  moisten  the  food ;  some  of  it  is 
needed  between  meals  to  keep  the  mouth  and  throat 
moist. 

Water  a  Poor  Substitute.  —  Water  will  moisten  food 
too  ;  we  can  eat  much  faster  if  we  drink  as  we  eat.  But 
the  water  cannot  make  the  changes  in  the  food  that 
are  produced  by  the  saliva.  If  you  soak  a  bit  of  bread 
in  water,  it  gets  soft  and  soggy  but  otherwise  it  tastes 
the  same  as  before.  If  you  chew  a  piece  of  bread  fine, 
until  it  is  moistened  with  saliva,  it  begins  to  have  a 
sweet  taste.  That  is  because  the  saliva  has  begun 
the  digestion  of  the  bread  by  changing  some  of  the 
starch  into  sugar.  Saliva  does  not  act  in  this  way  on 
any  except  the  starchy  foods,  but,  as  we  shall  see  later, 
it  is  important  that  the  work  of  digesting  starch  should 
be  well  begun  before  it  reaches  the  stomach.  If  we 
use  vinegar  on  our  food,  we  make  it  sour,  and  that 
greatly  interferes  with  the  digestion  of  starch  in  the 
mouth. 

Athletes  who  are  working  hard  use  chewing  gum  to 
increase  the  amount  of  saliva  in  the  mouth.  In  ordinary 
life,  this  is  neither  necessary  nor  desirable.  Continuous 
use  of  chewing  gum  is  actually  harmful ;  for  it  forces  the 
salivary  glands  to  work  overtime  and  thus  unfits  them 
for  their  regular  work. 

Secretion  of  the  Saliva.  —  Excitement  of  any  sort  will 
often  interfere,  temporarily,  with  the  secretion  of  saliva. 
We  all  know  that  when  we  are  badly  frightened  our 
mouths  feel  dry;  that  is  because  the  fright  has  stopped 


THE  FIRST  STEP  IN  DIGESTION  45 

the  action  of  the  salivary  glands.  An  amusing  use  was 
once  made  of  this  fact.  A  man  who  was  convinced  that 
one  of  his  servants  was  a  thief  called  all  his  servants 
together  and  told  them  about  his  losses.  Then  he  said 
that  he  was  going  to  give  each  of  them  a  mouthful  of  dry 
meal  and  that  those  who  were  innocent  of  the  theft 
would  be  able  to  swallow  it  while  the  thief  could  not. 
That  was  exactly  what  happened ;  one  of  the  servants 
was  utterly  unable  to  swallow  the  meal  and  he  confessed 
to  being  the  thief.  He  had  been  so  frightened  lest  he 
should  betray  himself  that  the  fear  had  stopped  the 
secretion  of  saliva  and  he  could  not  moisten  the  meal 
sufficiently  to  swallow  it.  The  other  servants  not  being 
guilty  were  not  afraid  and  had  no  difficulty  in  swal- 
lowing. 

Eating  in  a  Hurry.  —  There  are  evidently  good  reasons 
why  we  should  chew  our  food  well,  taking  plenty  of  time 
to  eat  each  meal ;  half  an  hour  is  none  too  long  when  the 
meal  consists  of  solid  food.  But  what  can  we  do  when 
we  are  in  a  hurry?  We  should  eat  slowly  even  though 
that  may  involve  eating  less  than  usual.  A  little  food, 
properly  eaten  and  relished,  will  do  more  good  than  a  full 
meal  that  has  to  be  "  bolted." 

The  fire  in  a  wood  stove  has  to  be  tended  constantly, 
or  else  it  will  go  out.  Is  it  the  same  with  our  bodies? 
Are  we  in  danger  of  having  to  stop  work  some  afternoon 
for  lack  of  strength,  in  case  we  do  not  have  time  to  eat 
the  usual  amount  of  food  at  our  midday  meal?  For- 
tunately, we  are  not.  In  fact  the  food  that  we  eat  at 
noon  to-day  is  not  really  used  by  our  bodies  before  to- 
morrow —  so  much  has  to  happen  to  it  before  it  is  ready 


46 


PHYSIOLOGY   AND   HEALTH 


to  give  us  energy  and  heat.     If  you  are  obliged  to  cut 
your  midday  meal  short  to-day,  eat  slowly  as  much  as 

you  have  time  to 
eat ;  then  at  the  next 
meal  you  can  eat  a 
little  more  than 
usual,  if  you  need  it, 
to  make  up  for  the 
meal  that  you  had  to 
cut  short. 

Drinking  Water 
with  Meals. —  Drink- 
ing water  with  meals 
has  been  considered 
unwise,  on  the  theory 
that  the  water  would 
so  dilute  the  digestive 
juices  that  they  could 
not  work  as  vigor- 
ously upon  the  foods. 
That  seemed  a  reason- 
able conclusion  until 
it  was  put  to  the  test. 
Recently  careful  tests 
have  been  made  by  giving  a  number  of  healthy  young 
men  a  certain  amount  of  food  for  several  days;  one 
day  they  were  given  with  it  only  a  small  quantity  of 
water,  the  next  day  they  were  given  large  quantities  of 
water.  Most  careful  studies  were  then  made  as  to  the 
digestion  of  the  food.  After  many  tests  of  this  sort  it 
was  clearly  proved  that  food  is  better  digested  and  ab- 


FIG.  14.  —  He  had  better  take  his  lunch  with 
him  than  to  eat  it  in  this  way. 


THE   FIRST  STEP   IN   DIGESTION  47 

sorbed  when  considerable  quantities  of  water  are  taken 
with  the  meals. 

The  earlier  belief  that  water  checked  digestion  was  thus 
proved  to  be  a  mistake,  but  that  does  not  warrant  its 
use  in  the  wrong  way.  We  should  not  drink  with  each 
mouthful  to  save  the  time  and  trouble  of  chewing  food. 
Water  makes  a  good  "  last  course  "  at  any  meal,  and 
it  is  all  right  between  mouthfuls  but  not  with  them. 

The  Kind  of  Relish  That  Helps  Digestion.—  It  has  been 
proved  by  many  experiments  that  when  we  enjoy  eating 
a  meal,  it  is  better  digested  than  when  we  are  indifferent 
to  it,  or  when  we  make  a  fuss  about  having  to  eat  some 
dish  we  do  not  care  for.  This  means  that  we  ought  to 
learn  to  like  various  kinds  of  foods ;  it  is  possible,  for 
you  will  find  that  people  who  have  traveled  much,  in 
various  parts  of  the  world,  eat  and  enjoy  eating  a  great 
variety  of  dishes.  We  should  also  cultivate  the  habit  of 
being  cheerful  at  mealtime  and  of  talking  only  of  pleasant 
things. 

Good  Teeth  Help  Digestion.  —  The  teeth  are  a  set  of 
tools,  of  different  sizes  and  shapes,  to  be  used  in  prepar- 
ing the  food  for  digestion  in  the  stomach.  The  front 
teeth  have  sharp  edges  for  biting  food ;  those  just  back 
of  them  are  better  for  tearing  it ;  those  still  further  back 
have  broader  surfaces  for  grinding  the  food  into  a  fine 
mass.  Tools  always  have  to  be  taken  care  of  if  they  are 
to  do  good  work.  If  the  teeth  are  in  good  condition,  chew- 
ing the  food  is  a  pleasure ;  when  they  are  decayed,  a  person 
is  inclined  to  spare  them  and  thus  to  throw  part  of  their 
work  on  the  stomach  ;  this  paves  the  way  for  indigestion. 

Bad  teeth,  besides  making  the  mouth  look  unsightly, 


48 


PHYSIOLOGY   AND    HEALTH 


give  one  a  foul-smelling  breath,  and  they  may  be  the 
cause  of  sores  in  the  mouth.  So  it  is  a  matter  of  great 
importance  that  the  teeth  should  be  kept  in  good  con- 
dition. Some  cities  have  the  teeth  of  the  school  children 
inspected  at  regular  intervals.  That  is  because  they 
have  found  that  when  bad  teeth  are  put  into  proper 


FIG.  15.  —  THE  TEETH  OF  AN  ADULT. 
C,  canine  teeth;  Bi,  bicuspids;  /,  incisors;  M,  molars. 

condition,  a  pupil  often  improves  not  only  in  his  general 
health  but  also  in  his  class  work. 

How  Teeth  Are  Injured.  —  The  outside  of  a  tooth  is 
very  hard,  but  it  is  also  brittle,  like  glass ;  the  inside  is 
much  softer.  As  long  as  the  hard  outside,  called  enamel, 
remains  unbroken  the  tooth  continues  to  be  sound  and 
healthy.  If  the  enamel  is  cracked,  so  that  the  food  we 


THE   FIRST   STEP   IN  DIGESTION  49 

eat  and  the  fluids  of  the  mouth  come  in  contact  with  the 
softer  bone  within  (dentine),  it  is  likely  to  begin  to  decay. 
The  crack  in  the  enamel  may  be  a  tiny  one,  but  inside  the 
tooth  the  trouble  will  spread,  until  it  is  necessary  to  cut 
out  some  of  the  soft  part  of  the  tooth  (pulp)  to  stop  the 
decay.  When  that  is  done,  the  dentist  puts  in  some 
kind  of  "  filling  "  that  is  suitable  to 
take  the  place  of  the  soft  part  he 
had  to  cut  away. 

Picking  the  teeth  with  needles  or 
pins  may  scratch  the  enamel,  and 
the  result  may  be  a  crack  in  the 
tooth.  The  same  thing  is  likely  to 
happen  when  nuts  or  other  hard 
substances  are  cracked  with  the 
teeth. 

Why  We  Brush  the  Teeth.  —  Per- 
haps  most  of  us  brush  our  teeth  FIG.  IG.-A  SINGLE  TOOTH. 

i  , -i  111    This  figure  shows  the  rela- 

because  we  want  them  to  look  and     tion  of  parts  and  also  the 

feel     Clean;     that     WOUld     be     reason        formation    of  a    decayed 

enough,  but  there  is  another  reason  spot> 
why  we  need  to  do  it.  When  we  eat,  particles  of  food 
lodge  between  the  teeth ;  if  they  are  not  removed,  decay 
of  the  teeth  may  start  from  these  food  particles.  So  it 
is  well  to  brush  the  teeth  after  every  meal,  or  at  least 
every  night  and  every  morning.  A  stiff  toothbrush  is 
best.  It  should  be  used  up  and  down  the  teeth,  as  well 
as  from  side  to  side ;  this  dislodges  the  particles  of  food 
between  the  teeth.  It  is  as  necessary  to  brush  the  back 
teeth  as  the  front  teeth,  and  the  inner  surfaces,  next  the 
tongue,  need  brushing  as  well  as  the  outer  surfaces. 


50 


PHYSIOLOGY   AND   HEALTH 


Removal  of  Food  Particles.  —  Even  careful  brushing 
will  not  wholly  remove  the  food  particles ;  occasion- 
ally it  is  best  to  use  a  soft  toothpick,  or  a  piece  of 
strong  silk  thread  that  can  be  run  between  the  teeth 
without  injuring  them  or  the  gums  around  them.  Den- 
tal floss  is  excellent  for  this  purpose.  If  we  are  thorough 
in  this  care  of  the  teeth,  we  can  go  to  the  dentist 
without  being  afraid  that  he  will  find  large  cavities  in 

them.  Every  one 
should  have  his  teeth 
examined  by  a  den- 
tist twice  a  year. 
This  applies  to  chil- 
dren as  well  as  to 
adults ;  for  if  the  milk 
teeth  are  neglected, 
the  permanent  teeth 
that  follow  them  are 
likely  to  be  imperfect. 
In  the  care  of  the 
teeth  there  is  one 
motto  to  be  remem- 
bered constantly;  if 
it  could  be  printed  so 
black  that  every  per- 
son who  reads  it 
would  remember  it, 
not  only  toothache  but  much  illness  would  be  prevented : 
A  clean  tooth  never  decays. 

The  Growth  of  the  Teeth.  —  Babies  are  born  without 
teeth.  When  a  child  is  five  or  six  months  old,  the  first 


Artery 
Nerve 

• 

FIG.  17.  —  BABY  TEETH  AND  ADULT  TEETH. 

The  upper  figure  shows  the  baby  teeth  and 
above  them  the  adult  teeth  which  are  to 
grow  and  push  out  the  baby  teeth.  The 
lower  figure  is  the  lower  jaw  of  an  adult. 


THE  FIRST  STEP  IN   DIGESTION  51 

set,  called  temporary  or  milk  teeth,  begin  to  come  through 
the  gums.  By  the  time  he  is  about  three  years  old,  he 
has  twenty  teeth,  ten  on  each  jaw.  When  he  is  six  or 
seven  years  old,  the  permanent  teeth  begin  to  appear. 
They  are  formed  in  the  jaw  above  the  milk  teeth,  which 
loosen  to  make  way  for  them.  In  the  temporary  set 
there  are  only  two  molars  on  each  side  of  the  jaw.  The 
first  of  the  permanent  teeth  to  come  through  are  the 
"  six-year  molars. ' '  They  are  often  neglected  and  allowed 
to  decay  because  they  are  thought  to  be  the  last  of  the 
milk  teeth.  If  a  child  of  six  or  seven  has  three  double 
teeth  on  one  side  of  the  jaw,  the  one  which  came  last  is  a 
permanent  tooth.  While  the  permanent  teeth  are  form- 
ing, the  child's  jaw  is  also  growing  larger,  so  by  the  time 
he  is  eighteen  there  is  usually  room  for  the  thirty-two 
large  teeth  that  make  the  permanent  set.  Or  it  may  be 
that  the  last  four  teeth,  called  wisdom  teeth,  will  not 
come  before  he  is  twenty-five.  These  teeth  are  longer 
and  stronger  than  the  first  set  and  with  proper  care 
should  last  for  the  remainder  of  one's  life. 

The  Parts  of  a  Tooth.  —  The  part  of  the  tooth  that 
we  see  is  called  the  crown;  the  part  called  the  neck  is 
surrounded  by  the  gums ;  the  root  fits  into  the  socket  inr 
the  jaw  bone,  where  it  is  well  anchored.  Every  healthy 
tooth  is  alive  and  so  it  has  to  be  fed.  Its  food  comes 
through  a  tiny  blood  vessel  which  passes  up  through  the 
root.  A  nerve  also  runs  through  the  root ;  were  it  not 
for  this  nerve,  which  aches  when  it  is  exposed  to  the  air, 
a  tooth  might  decay  so  badly  that  it  would  crumble  be- 
fore we  noticed  that  there  was  anything  the  matter  with  it. 
Toothache  is  a  danger  signal. 


52  PHYSIOLOGY   AND    HEALTH 


QUESTIONS 

1.  Why  does  food  need  to  be  digested?    What  would  happen  if 
you  could  not  digest  your  food? 

2.  Drop  a  square  of  lump  sugar  into  a  glass  of  water.     Break 
another  lump  into  several  small  pieces  and  drop  them  into  a  glass  of 
water.     Watch  and  see  whether  the  sugar  in  the  first  or  second  glass 
dissolves  more  quickly. 

3.  Would  you  conclude  from  this  experiment  that  it  is  extremely 
hard  work  for  the  stomach  to  digest  a  meal  that  is  eaten  in  a  hurry  ? 

4.  How  long  a  time  do  you  usually  spend  in  eating  your  breakfast  ? 
Your  dinner  ?     Your  luncheon  ? 

5.  What  are  the  two  uses  of  saliva?    Could  we  swallow  any  of 
our  foods  without  saliva? 

6.  Why  does  a  dog  lick  his  chops  when  you  tempt  him  with  a  piece 
of  meat  ? 

7:   What  precautions  should  one  take  when  drinking  water  with 
meals  ? 

8.  Why  is  it  best  not  to  tell  any  exciting  or  distressing  news  at  meal- 
time? 

9.  Can  you  see  any  reason  for  the  saying  "Laugh  and  grow  fat"? 

10.  Why  would  it  not  be  best  to  take  our  food  —  supposing  we 
could  —  in  the  form  of  tasteless  pellets  ? 

11.  Can  you  think  of  any  reasons  why  poor  teeth  mean  ill  health? 

12.  What  are  some  of  the  causes  of  decay  of  the  teeth  ? 

13.  What  may  happen  to  one's  teeth  if  he  uses  them  for  cracking 
nuts  or  picks  them  with  a  pin  or  needle  ? 

14.  How  many  people  you  know  have  perfectly  sound  teeth  ?     How 
have  they  kept  them  in  good  condition  ? 

15.  How  often  do  you  brush  your  teeth?    What  kind  of  tooth- 
brush have  you?     Do  you  use  dental  floss? 

16.  Try  to  figure  out  which  will  take  more  time :  to  rinse  or  brush 
one's  teeth  after  each  meal,  or  to  have  one  or  two  decaying  teeth  filled 
by  a  dentist  each  year.    Which  is  more  trouble  and  expense? 

17.  At  what  age  should  one  begin  to  have  his  teeth  cared  for? 


CHAPTER  VIII 
DIGESTION   IN   THE   STOMACH 

WE  do  not  eat  in  order  to  feed  the  stomach,  it  is  the 
other  way  about ;  the  stomach  works  from  eight  to 
twelve  hours  every  day  to  do  its  share  toward  feeding 
the  rest  of  the  body.  We  have  to  tell  our  hands  what 
we  wish  them  to  do,  but  the  stomach  does  its  work  with- 
out our  attention.  At  the  same  time  we  can  help  or 
hinder  its  action.  In  case  we  permit  ourselves  to  be 
ill  natured  when  we  are  eating,  we  interfere  with  the 
work  the  stomach  wants  to  do.  Another  common  mis- 
take is  to  deprive  the  stomach  of  its  rest.  It  ought  to 
have  a  chance  to  rest  between  meals,  when  its  work  is 
completed. 

Swallowing.  —  When  the  food  is  fine  enough  to  be 
swallowed  does  it  fall  down  the  throat  ?  No,  and  swallow- 
ing is  not  so  simple  a  process  as  it  seems.  Chewing  is 
under  our  control,  and  we  also  control  the  tongue  as  it 
pushes  the  food  back  into  the  throat,  which  is  the  first 
act  in  swallowing.  But  after  the  food  passes  into  the 
top  of  the  gullet  or  esophagus  (the  tube  that  connects  the 
mouth  with  the  stomach)  the  muscles  of  the  gullet  close 
behind  it  and  send  it  down,  in  a  series  of  pushes  of  which 
we  are  not  conscious.  Even  water  does  not  run  down  the 
gullet,  but  is  pushed  down  by  the  muscles.  Did  you 

53 


54 


PHYSIOLOGY   AND   HEALTH 


ever  see   an  acrobat 
glass   of  water ;    or  a 


Vermiftrm  Appendi 


FIG.  18.  —  THE  DIGESTIVE  ORGANS  VIEWED  FROM 
IN  FRONT. 

In  this  figure  the  liver  and  stomach  are  represented  as 
separate  from  each  other.  There  is  in  reality  no 
break  in  the  intestine,  but  it  was  placed  in  the  figure 
in  order  to  show  the  separate  organs  which  in  their 
proper  position  more  or  less  cover  each  other. 


stand  on  his  head  and  drink  a 
horse  drinking  out  of  a  brook 
and  thus  swallow- 
ing upwards  ?  A 
few  seconds  after 
we  let  the  water 
start  down  the 
gullet  it  reaches 
the  gourd-shaped 
bag  that  we  call 
the  stomach. 

Location  of  the 
Stomach.  —  The 
only  way  into 
the  stomach  is 
through  the 
mouth.  Figure 
18  shows  the 
stomach,  but 
many  a  person 
cannot  locate  his 
own  stomach  ac- 
curately,  even 
after  studying 
such  a  picture. 
So  pupils  are  ad- 
vised to  consult 
and  to  copy  the 
outline  figure 
found  on  page 
422.  That  shows 


DIGESTION  IN  THE   STOMACH  55 

how  the  different  digestive  organs  are  situated  with 
reference  to  each  other. 

How  the  Stomach  Works.  —  The  entrance  to  the 
stomach  from  the  gullet  is  guarded  by  a  small  fold  of 
muscle  which  acts  as  a  valve  and  closes  behind  the  food ; 
this,  under  ordinary  conditions,  prevents  the  food  from 
passing  back  from  the  stomach  to  the  gullet.  In  case  we 
eat  something  that  disagrees  with  us  badly,  the  stomach 
may  finally  reject  it.  Then  we  have  a  feeling  of  nausea; 
we  say  that  we  are  "  sick  to  the  stomach  " ;  and  finally 
this  valve  opens  and  the  contents  of  the  stomach  are 
"  thrown  up  "  or  vomited,  thus  relieving  us.  There  is 
another  muscle  fold  (the  pyloric  valve)  that  closes  the 
other  end  of  the  stomach  and  prevents  the  food  from 
passing  out  before  the  stomach  has  completed  its  work. 

The  stomach  stretches  when  food  is  put  into  it,  and 
then  contracts  when  the  food  passes  out.  Its  inside  walls 
have  a  variety  of  muscles  so  placed  that  they  keep  the 
food  in  constant  motion  while  digestion  is  going  on. 
Like  a  churn,  the  stomach  moves  its  contents  back 
and  forth  and  tumbles  it  about ;  there  is  less  motion 
in  the  upper  part,  where  the  food  enters,  than  in  the 
lower  part. 

The  Gastric  Juice.  —  Besides  churning  the  food,  the 
stomach  also  pours  upon  it  and  mixes  with  it  a  consider- 
able quantity  of  a  digesting  fluid  that  is  called  gastric 
juice.  This  is  made,  as  it  is  needed,  by  thousands  of 
tiny  glands  (gastric  glands)  that  line  the  inner  surface 
of  the  stomach.  (See  colored  insert,  page  138.)  These 
glands  may  be  compared  to  tiny  bottles  with  their  mouths 
opening  into  the  stomach ;  only  the  gastric  glands,  un- 


56  PHYSIOLOGY   AND   HEALTH 

like  bottles,  make  the  fluid  which  drops  into  the  stomach 
through  their  open  mouths  and  so  is  poured  upon  the 
food.  The  amount  of  gastric  juice  made  in  a  day  would 
vary,  with  the  person  and  with  the  food  eaten,  from  a 
pint  and  a  half  to  three  pints. 

Action  of  the  Gastric  Juice  on  Proteins  and  Fats.  — 
As  soon  as  the  food  enters  the  stomach,  the  glands  begin 
to  pour  gastric  juice  upon  it.  At  the  same  time  the 
stomach  begins  its  churning  motions  which  mix  the  food 
with  the  gastric  juice.  Meat,  one  of  the  most  common 
forms  of  protein,  is  made  up  of  countless  minute  threads, 
called  muscle  fibers,  which  are  glued  together  into  little 
bundles  (see  Figure  56).  Scattered  through  the  muscle 
fibers  there  are  also  fat  cells  (see  Figure  4)  which  are 
held  together  by  tiny  fibers ;  each  of  these  cells  contains 
a  little  drop  of  fat. 

The  first  action  of  the  gastric  juice  is  to  dissolve  the 
gluey  substance  that  holds  the  muscle  fibers,  and  also 
the  thread-like  fibers  that  hold  the  fat  drops.  Then  the 
muscle  fibers  fall  apart,  and  the  fat  drops,  also  set  free, 
are  melted  by  the  heat  of  the  body.  The  result  is  that 
the  meat  becomes  more  or  less  liquid ;  it  begins  to  be 
dissolved  by  the  water  that  is  in  the  stomach.  Gastric 
juice  acts  in  a  similar  way  on  the  coagulated  white  of 
egg,  and  on  cheese  and  all  other  proteins. 

The  Digestion  of  Milk.  —  After  a  hearty  meal  a  baby 
often  throws  up  part  of  its  milk  in  a  curdled  condition. 
We  can  watch  the  curdling  process  if  we  put  a  little 
rennet  into  a  cup  of  milk  warmed  to  about  98°,  the 
temperature  of  the  body.  Use  a  teaspoonful  of  rennet  or 
one  of  the  rennet  tablets  sold  by  druggists.  In  the 


DIGESTION   IN  THE  STOMACH  57 

course  of  half  an  hour  the  milk  will  be  curdled.  Notice 
that  the  curd,  which  is  casein,  is  a  solid  mass.  In  the 
case  of  the  baby,  the  curdling  of  the  milk  does  not  mean 
that  its  stomach  is  "  too  sour."  It  means  that  the  baby 
has  eaten  too  much,  and  the  stomach  cannot  hold  it  all ; 
the  fact  that  the  milk  is  curdled  only  shows  that  the  rennet 
in  the  gastric  juice  is  properly  digesting  it.  If  it  were  not 
curdled,  we  should  feel  sure  that  something  was  wrong ; 
for,  since  the  gastric  juice  is  acid  and  contains  rennet,  the 
curdled  condition  of  the  milk  is  an  indication  that  the 
stomach  has  been  doing  its  work. 

The  second  action  of  the  gastric  juice  on  the  milk  curd 
is  to  begin  to  convert  it  again  into  a  liquid,  so  that  it 
can  be  taken  into  the  blood. 

Starch  and  Sugar  in  the  Stomach.  —  Gastric  juice  does 
not  digest  starch.  When  we  chew  starchy  foods  a  long 
time,  we  give  the  saliva  in  the  mouth  a  chance  to  begin 
changing  them  into  sugar;  then  when  they  reach  the 
stomach,  the  saliva  goes  on  working  as  long  as  it  can. 
In  the  upper  end  of  the  stomach,  which  is  more  or  less 
quiet,  the  saliva  may  work  for  some  time ;  but  finally 
the  sour  gastric  juice  makes  the  starchy  food  sour,  and 
then  the  saliva,  not  being  able  to  work  on  sour  food,  can 
do  no  more  digesting.'  Nothing  further  happens  to  the 
starch  until  after  it  leaves  the  stomach. 

Sugar  readily  dissolves  in  water ;  hence  the  sugar 
found  in  fruits  is  ready  to  go  into  the  blood  as  soon  as  it 
is  dissolved  by  the  water  in  the  stomach.  That  is  not 
the  case  with  our  highly  concentrated  cane  sugar.  Cane 
sugar  has  to  be  changed  before  the  body  can  use  it,  but 
the  change  does  not  take  place  in  the  stomach. 


58  PHYSIOLOGY   AND   HEALTH 

Watching  the  Process  of  Digestion.  —  One  fortunate 
doctor  had  many  opportunities  to  watch  the  process  of 
digestion.  A  patient  by  the  name  of  Alexis  St.  Martin 
was  sent  to  him  suffering  from  a  gunshot  wound  that 
had  pierced  the  walls  of  the  stomach.  When  the  wound 
healed  it  left  an  opening  into  the  stomach  which  was 
covered  by  a  flap  that  could  be  pushed  aside.  The  doctor 
was  quick  to  see  that  this  gave  him  a  wonderful  oppor- 
tunity to  watch  a  stomach  at  work.  He  made  obser- 
vations for  several  years,  noting  what  kinds  of  foods 
remained  longest  in  the  stomach,  and  what  kinds  were 
made  ready  for  the  intestine  in  a  comparatively  short 
time  and  how  the  man's  conduct  after  eating  af- 
fected the  action  of  the  stomach.  His  reports  covered 
many  of  the  facts  that  have  already  been  given  in 
this  chapter. 

Much  of  what  he  saw  was  then  entirely  new  to  students 
who  were  studying  the  process  of  digestion,  and  because 
they  could  not  account  for  some  of  the  things  this  doctor 
reported,  they  began  to  think  that  he  was  not  an  accurate 
observer.  So  as  the  years  went  on,  and  nothing  happened 
to  confirm  his  reports,  investigators  began  to  laugh  at 
the  elaborate  notes  made  by  that  doctor ;  they  said  that 
he  had  used  his  imagination  more  than  his  eyes. 

X-Rays  of  Digestive  Process.  - —  Many  years  later  came 
the  wonderful  discovery  of  the  X-rays  which  have  made 
it  possible  to  learn  so  much  about  what  goes  on  inside  the 
body.  It  was  found  that  the  progress  of  food  through 
the  digestive  organs  could  be  watched  if  the  food  was 
mixed  with  bismuth,  a  harmless  substance  that  makes 
it  opaque  so  that  it  can  be  seen  by  the  X-rays.  When 


DIGESTION  IN  THE  STOMACH  59 

the  X-ray  confirmed  much  of  what  the  doctor  had  seen, 
people  began  to  study  his  records  once  more. 

Countless  experiments  have  been  made  with  small  ani- 
mals because  they  are  more  easily  observed.  The  animals 
are  fed  the  food  they  like,  plus  bismuth,  and  successive 
X-ray  photographs  are  then  taken.  These  photographs  in- 
dicate that  an  ordinary  meal  will  stay  in  the  stomach  of  a 
cat  for  an  hour  or  two  before  it  is  digested  well  enough  to  go 
on  into  the  intestine.  But  if  just  after  the  meal  is  swal- 
lowed anything  occurs  to  frighten  or  disturb  the  cat,  the 
stomach  ceases  to  do  its  work  properly  and  the  food  will  re- 
main in  it  for  hours,  without  being  digested.  The  fright 
interferes  with  digestion  by  stopping  both  the  secretion  of 
gastric  juice  and  the  action  of  the  muscles  of  the  stomach. 

Sleep  and  Digestion.  —  When  the  animal  goes  to  sleep 
right  after  swallowing  a  meal,  the  food  stays  a  long  time 
in  the  stomach  without  digesting.  It  has  been  observed 
that  babies  go  to  sleep  as  soon  as  they  have  had  their  milk ; 
from  this  it  has  been  argued  that  to  sleep  after  eating 
was  natural  and  therefore  healthful.  Evidently  it  is 
natural  for  babies,  who  ought  to  sleep  most  of  the  time 
anyway  ;  but  it  does  not  follow  that  grown  people,  whose 
habits  are  very  different,  ought  to  take  naps  after  eating. 
X-ray  observations  of  animals  indicate  that  a  nap  is 
likely  to  delay  digestion.  Perhaps  the  baby's  sleeping 
may  be  explained  by  the  fact  that  food  calls  the  blood 
to  the  stomach,  and  as  the  baby  has  few  interests  to  keep 
his  brain  active,  he  just  drops  off  to  sleep  when  the  activ- 
ity of  the  stomach  calls  part  of  the  blood  from  the  brain. 
Grown  people,  having  more  to  do  and  to  think  about,  can 
easily  and  naturally  keep  awake  under  those  circumstances. 


60  PHYSIOLOGY   AND   HEALTH 


QUESTIONS 

1.  What  part  of  swallowing  can  you  control? 

2.  How  is  food  prevented  from  going  from  the  stomach  into  the 
intestine  before  it  is  properly  digested  ? 

3.  Does  food  ever  pass  from  the  stomach  back  into  the  gullet? 
Under  what  conditions? 

4.  What  happens  to  meat  in  the  stomach?     To  the  white  of  egg? 

5.  What  happens  to  starch  in  the  stomach?     To  milk? 

6.  If  you  chew  your  food  thoroughly,  where  will  the  digestion  of 
meat  begin?     How  about  bread? 

7.  About  how  long  will  food  remain  in  the  stomach? 

8.  Why  will  food  remain  longer  in  the  stomach,  if  the  person  is 
irritated  or  frightened  at  mealtime  ? 

9.  Can  you  explain  how  a  horse  drinking  from  a  brook  can  swallow 
up  into  his  stomach? 

10.  What  does  the  fact  that  milk  curdles  in  the  stomach  indicate 
about  the  gastric  juice? 

11.  Where  is  the  gastric  juice  made? 

12.  Explain  how  men  have  been  able  to  learn  so  much  about  the 
process  of  digestion. 

To  THE  TEACHER.  Artificial  gastric  juice  may  be  prepared  by  dis- 
solving ten  grains  of  pepsin  powder  in  a  half  pint  of  water  and  adding 
about  twenty  drops  of  strong  hydrochloric  acid.  Have  pupils  mix 
two  or  three  teaspoonfuls  of  fresh  milk  with  a  few  drops  of  this  solution 
and  keep  at  about  100°  F.  Have  them  observe  and  comment  upon  the 
result. 

Secure  if  you  can  and  bring  to  class  X-ray  photographs. 


CHAPTER  IX 
DIGESTION   AND   ABSORPTION  IN  THE  INTESTINES 

WHEN  the  food  passes  out  from  the  further  end  of  the 
stomach,  it  goes  into  the  intestines,  also  called  the  bowels 
(see  Figure  18).  This  food  contains  much  undigested 
starch ;  some  proteins  and  fats  whose  digestion  was  not 
completed  in  the  stomach ;  and  all  of  the  cane  sugar  in 
undigested  form.  Much  remains  to  be  done  in  the  in- 
testines, which  are  assisted  in  this  work  by  other  organs. 
These  will  be  described  before  we  trace  the  process  of 
digestion  further. 

Any  one  who  makes  small  paper  models  of  the  organs 
(see  pages  422  and  423)  and  places  them  as  they  lie  in 
the  body  will  get  a  clear  idea  of  their  relations.  It  is 
difficult  to  make  this  plain  in  the  figures  because  of  the 
way  in  which  one  organ  overlaps  another. 

The  Intestines.  —  Look  at  Figure  18  and  you  will 
see  just  below  the  stomach  a  very  much  coiled  tube. 
The  smaller  part  of  it  has  many,  many  folds ;  the  larger 
part,  which  goes  around  the  coils,  is  shaped  like  the 
letter  U  turned  upside  down.  The  smaller  part,  which 
is  connected  with  the  stomach,  is  called  the  small  intes- 
tine ;  it  is  about  twenty  feet  long  and  about  an  inch  in 
diameter.  The  much-coiled  small  intestine  opens  into 
the  larger  U-shaped  tube,  called  the  large  intestine, 

61 


62  PHYSIOLOGY   AND   HEALTH 

which  is  some  five  feet  long  and.  about  two  and  a  half 
inches  in  diameter.  Long  as  these  tubes  are,  they  do 
not  begin  to  represent  the  length  of  the  journey  that  the 
food  has  to  make  before  it  is  either  fully  digested  or  sent 
out  of  the  body  as  waste.  The  continual  churning  of  the 
food  in  the  stomach  and  intestines  keeps  it  in  such  con- 
stant motion  that  the  actual  distance  it  travels  is  even, 
longer  than  one  would  suppose  from  the  extent  of  the 
digestive  system. 

The  Liver.  -  -  The  human  liver  looks  very  much  like 
that  of  an  ox.  It  is  dark  red  in  color  and  weighs  several 
pounds ;  it  is  located  at  the  right  of  the  stomach  and  a 
little  above  it  (see  Figure  18).  As  it  is  one  of  the 
largest  organs  in  the  body,  we  might  conclude  that  it 
has  some  important  work  to  do.  One  thing  that  it  does 
is  to  produce  a  liquid  called  bile  or  gall,  which  flows  into 
the  intestine  when  food  enters  it.  This  liquid  helps 
the  intestines  in  their  work,  especially  in  digesting  fats. 
The  assistance  rendered  the  intestines  is  not,  however, 
of  sufficient  importance  to  account  for  the  fact  that  the 
liver  produces  a  pint  or  more  of  bile  every  day.  It 
appears  to  be  largely  waste  matter  that  is  taken  out  of 
the  blood  by  the  liver,  and  is  poured  into  the  small  in- 
testine so  that  it  may  be  removed  from  the  body,  with 
the  waste  products  of  digestion. 

When,  for  any  reason,  the  action  of  the  liver  is  impaired, 
the  skin  grows  yellow  and  illness  may  result ;  the  person 
is  said  to  be  bilious,  and  in  severe  cases  is  said  to  have 
jaundice.  The  trouble  in  these  cases  seems  to  be  that 
the  bile,  instead  of  being  freely  discharged  into  the  in- 
testine, is  held  back  and  absorbed  by  the  blood. 


DIGESTION  AND   ABSORPTION   IN  THE   INTESTINES     63 

The  Pancreas.  —  Just  below  the  stomach  is  a  long, 
thin  gland,  called  the  pancreas  (see  Figure  18).  It  pro- 
duces a  liquid  called  the  pancreatic  fluid,  which  passes 
into  the  intestines.  The  food  from  the  stomach  is  mixed 
with  the  bile  from  the  liver  and  the  fluid  from  the  pancreas 
almost  as  soon  as  it  enters  the  intestines.  Of  all  the 
digestive  juices  this  is  the  most  important.  By  itself 
it  can  digest  all  kinds  of  food,  and  it  completes  what  the 
other  digestive  juices  have  not  been  able  to  finish.  There 
have  been  cases  in  which  it  was  found  necessary  to  re- 
move the  stomach  completely,  so  that  the  food  passed 
directly  from  the  gullet  into  the  intestine.  The  pan- 
creatic juice  was  then  found  to  be  sufficiently  powerful 
to  do  the  entire  work  of  digestion. 

The  Enzymes.  —  All  the  digestive  juices  —  saliva, 
gastric  juice,  pancreatic  juice  —  contain  powerful  sub- 
stances called  enzymes.  Saliva  has  one  enzyme;  there 
are  two,  of  a  different  kind,  in  gastric  juice ;  and  several, 
still  different,  in  the  pancreatic  juice.  The  quantity  of 
enzyme  in  a  quart  of  any  one  of  these  juices  is  small 
(much  less  than  1  per  cent),  but  it  is  by  the  enzymes 
that  the  food  is  actually  digested. 

Foods  Are  Changed  in  the  Intestine.  — When  the  food 
mass  reaches  the  intestine  there  is  much  starch  in  it, 
for  all  the  starch  that  was  not  converted  into  sugar  by 
the  action  of  the  saliva  is  still  unchanged.  One  of  the 
enzymes  in  the  pancreatic  juice  turns  this  starch  into 
sugar  which,  after  being  dissolved  in  the  liquids  present 
in  the  intestine,  is  ready  to  be  absorbed  into  the  blood. 
Cane  sugar  is  also  transformed,  by  another  enzyme  of  the 
pancreatic  juice,  into  a  more  simple  form  of  sugar  which 


64  PHYSIOLOGY   AND    HEALTH 

can  be  used  by  the  body.  The  proteins  that  were  not 
fully  digested  by  the  stomach  are  quickly  acted  upon 
by  a  third  enzyme  in  the  pancreatic  juice.  The  drops 
of  fat,  which  in  the  stomach  were  only  freed  from  their 
coverings,  are  here  digested  by  the  combined  action  of 
the  bile  and  a  fourth  enzyme  in  the  pancreatic  juice, 
and  are  dissolved  in  the  liquids  in  the  intestine. 

The  process  of  digestion  in  the  small  intestine  takes 
from  two  to  four  hours ;  and  while  it  is  going  on,  the 
inner  walls  of  the  intestine  are  in  motion,  squeezing  the 
food,  and  mixing  it  with  the  digestive  juices  so  that  it 
may  become  dissolved.  Finally,  when  the  process  is 
completed,  the  food  is  in  liquid  form  and  is  ready  to  be 
taken  up  by  the  blood  and  sent  over  the  body. 

The  Large  Intestine.  —  The  portions  of  the  food  that 
remain  undigested  pass  from  the  small  intestine  into  the 
large  intestine,  together  with  the  bile  and  some  other 
materials.  Some  absorption  of  water  takes  place  there, 
but  there  is  little  further  digestion,  most  of  the  contents 
of  the  large  intestine  passing  out  of  the  body  as  waste. 
There  are  certain  vegetables  and  fruits  which  consist 
largely  of  material  that  is  not  digestible ;  yet  they  are 
useful  to  us  because  of  the  juices  they  contain,  and 
because  of  the  bulky  portion  of  them  that  remains  un- 
digested and,  in  passing  out  of  the  system,  bears  with  it 
other  wastes. 

Waste  Materials.  —  It  is  most  important  that  the 
waste  materials  should  pass  away  from  the  body  every 
day,  for  if  they  remain  in  the  intestine  they  make  trouble. 
This  waste  may  putrefy  even  in  the  intestine,  forming 
poisons  which  are  injurious  to  the  body.  With  a  little 


DIGESTION  AND  ABSORPTION   IN   THE   INTESTINES      65 

care,  it  is  easy  to  form  the  habit  of  expelling  the  waste 
at  a  regular  time  every  day;  the  body  likes  regularity 
and  will  readily  acquire  such  habits.  In  case  the  bowels 
become  sluggish,  exercise  in  the  open  air,  eating  fruit, 
and  choosing  coarse  food  will  help  the  body  to  get  ad- 
justed. The  regular  use  of  drugs  to  move  the  bowels 
is  a  great  mistake. 

Indigestion.  —  What  we  call  "  indigestion  "  may  show 
itself  in  a  pain  in  the  stomach  or  bowels,  in  nausea,  or  in 
diarrhea.  It  means  that  some  one  of  the  digestive 
processes  has  been  seriously  interfered  with ;  perhaps 
we  have  eaten  some  spoiled  food,  or  food  that  is  not 
suited  to  us ;  or  we  may  be  eating  too  much,  or  too 
rapidly.  The  best  way  to  relieve  indigestion  is  to  remove 
the  cause,  by  correcting  our  wrong  habits. 

How  Food  Is  Absorbed 

The  processes  of  digestion  here  described  have  gone 
on  from  six  to  eight  hours,  but  as  yet  the  body  has  not 
made  use  of  the  food  on  which  the  digestive  organs  have 
been  so  busily  at  work.  The  fact  is  that  little  of  it  can 
be  used  within  six  hours  after  eating;  and  much  of  it 
may  not  be  used  the  day  we  eat  it.  None  of  it  can  feed 
the  body  until  it  is  absorbed,  that  is,  until  it  is  taken 
into  the  blood.  There  is  a  little  absorption  from  the 
stomach,  and  some  from  the  large  intestine  ;  but  any  one 
who  had  to  live  upon  what  is  absorbed  by  those  two 
organs  would  soon  starve  to  death,  no  matter  how  much 
food  he  ate.  In  the  small  intestine  there  is  a  wonderful 
arrangement  by  which  the  digested  food  is  delivered  to 


66  PHYSIOLOGY  AND   HEALTH 

the  blood.  As  soon  as  this  transfer  is  made,  the  food 
can  be  carried  by  the  blood  everywhere  through  the 
body. 

The  Villi  of  the  Intestine.  —  How  does  the  food  get  out 
of  the  small  intestine  and  into  the  blood?  One  might 
think  it  would  be  emptied  into  the  blood,  as  the  con- 
tents of  the  stomach  are  emptied  into  the  small  intes- 
tine, but  a  much  better  and  safer  way  is  provided. 


Glands' 


Muscles'^' 

FIG.   19. —  THE  VILLI. 
A  small  piece  of  the  intestine  highly  magnified  and  showing  the  villi. 

The  inner  surface  of  the  small  intestine  is  covered  with 
tiny  projections  which,  like  little  fingers,  extend  into  the 
intestinal  tube.  They  are  so  small  that  they  can  just 
barely  be  seen  with  the  naked  eye.  There  are  millions 
of  them ;  and  they  give  the  inside  of  the  intestine  a  soft, 
velvety  surface.  They  are  named  villi.  It  is  their  duty 
to  take  the  liquefied  food  out  of  the  intestine  and  to  pass 
it  on  to  the  blood.  As  soon  as  the  partly  digested  food 
enters  the  intestine,  it  comes  into  contact  with  these  tiny 
villi;  it  is  tumbled  around  over  them,  by  the  motions 


DIGESTION  AND   ABSORPTION   IN  THE   INTESTINES     67 


of  the  intestinal  wall,  all  the  time  that  it  remains  in  the 
intestine. 

The  villi  are  able  to  make  their  selections  from  the  food 
materials  that  surround  them.  They  will  not  take  up 
waste  matter  or  food  that  is  not  properly  digested. 
An  experiment  like  that  represented  in  Figure  20  illus- 
trates how  they  do  this.  Take  a  short  piece  of  sausage 
skin  (which  really  comes  from  the 
walls  of  the  intestine  of  some  animal), 
fill  it  with  a  strong  solution  of  sugar, 
and  suspend  it  in  a  small  dish.  After 
half  an  hour  or  more,  taste  the  water 
in  the  dish;  it  will  be  found  to  be 
sweet.  Some  of  the  sugar  has  passed 
out  through  the  wall  of  the  sausage 
skin  into  the  dish  of  water.  In  much 
the  same  way  sugars  and  other  foods 
pass  from  the  intestines  into  the  villi.  FlG 

Small  as  the  villi  are,  each  one 
has  many  tiny  blood  vessels  inside 
it.  Some  of  these  blood  vessels  soak  up  the  sugars 
and  digested  proteins  taken  by  the  villus,  while  the 
fats  do  not  go  into  the  blood  vessels  at  all  —  which 
shows  that  the  villi  know  how  to  separate  the  food 
they  take  in.  The  fat  which  is  absorbed  passes  into 
a  tube  in  the  middle  of  the  villus ;  that  tube  is  printed 
in  black  in  the  colored  illustration,  page  102.  From 
the  villus  the  two  varieties  of  absorbed  food  are  carried 
in  different  directions.  The  sugars  and  digested  pro- 
teins, which  have  been  taken  into  the  blood  circulat- 
ing in  the  villus,  are  carried  in  the  blood  to  the  liver, 


20.  —  A  DIAGRAM 
SHOWING  THE  ABSORP- 
TION OF  FOOD. 


68 


PHYSIOLOGY   AND   HEALTH 


Arterif. 


Lodeal 


LymphGlond 


where,  as  we   shall   presently   see,   they   leave   part   of 
the  sugar. 

The  tube  in  each  villus  which  receives  the  fat  unites 
with  thousands  of  others  from  other  villi,  forming  tiny 
vessels  which  are  called  lacteals  (milk  holders),  so  called 
because  the  fat  inside  them  looks  at  this  time  white  like 

milk.  These  lacteals 
finally  all  unite  into 
one  rather  large  vessel 
that  passes  up  through 
the  chest  and  empties 
into  one  of  the  large 
blood  vessels  in  the 
neck.  Thus  all  the 
fat  is  poured  into  the 
blood  near  the  heart. 

The  Body's  Store- 
house. —  Every  work- 
ing part  of  the  body 
needs  a  constant  supply 
of  food.  After  a  meal 
a  large  amount  of 
liquid  food  from  the  intestines  is  poured  into  the  blood, 
then  it  may  be  hours  before  any  more  is  received.  If 
all  this  food  should  immediately  pass  to  the  working 
organs,  they  would  have  an  oversupply  for  the  time 
being,  and  then  a  great  scarcity  until  the  next  meal 
was  digested.  Such  irregularity  in  the  supply  of  food 
(and  hence  of  energy)  would  interfere  with  the  work 
of  the  body.  To  prevent  this,  the  food,  as  soon  as  it 
is  absorbed  by  the  blood,  is  carried  to  the  liver,  where 


FIG.  21. —  A  BIT  OF  THE   INTESTINE,  WITH 

VESSELS  CONNECTED  WITH  IT. 

The  figure  shows  arteries,  veins,  and  also  the 

lacteals  that  take  away  the  fatty  food. 


DIGESTION  AND   ABSORPTION   IN   THE   INTESTINES     69 

much  of  the  sugar  is  taken  out  of  the  blood  and  stored 
for  future  use.  Then  later,  when  the  active  organs  de- 
mand food,  the  liver  gives  up  its  store  to  the  blood. 
Thus  the  blood  contains  about  the  same  amount  of  food 
at  all  times.  If  there  is  more  sugar  in  the  blood  than 
the  liver  can  take  care  of,  the  liver  is  likely  to  get  out  of 
order  and  the  person  will  feel  "  out  of  sorts."  The  best 
remedy  is  to  eat  less  sugar  and  to  take  more  exercise  in 
the  open  air,  for  exercise  uses  up  the  excess  of  sugar. 

QUESTIONS 

1.  What  change  has  taken  place  in  the  food  between  the  time  when 
it  enters  the  stomach  and  the  time  when  it  passes  into  the  intestines? 

2.  What  work  remains  to  be  done? 

3.  How  long  is  the  large  intestine  ?    The  small  intestine  ? 

4.  How  can  tubes  of  this  length  be  contained  in  the  comparatively 
small  space  which  they  occupy? 

5.  What  is  bile?    What  is  its  use? 

6.  What  can  you  say  of  the  importance  of  the  pancreatic  juice? 
Is  it  more  or  less  important  than  the  gastric  juice? 

7.  What  are  the  enzymes?     What  fluids  contain  them?     What  is 
their  use? 

8.  Describe  the  process  of  digestion  in  the  small  intestine. 

9.  What  happens  to  food  if  it  is  kept  too  long  either  in  the  pantry 
or  in  the  intestine  ? 

10.  What  can  we  do  to  help  the  body  if  it  does  not  expel  wastes 
regularly? 

11.  What  is  the  purpose  of  digesting  food  ? 

12.  Describe  how  the  digested  food  gets  into  the  blood. 

13.  Trace  the  journey  of  a  piece  of  fat  meat  from  the  time  it 
is  swallowed  till  the  end  of  its  journey. 

14.  What  can  you  say  of  the  importance  of  the  liver  ? 

15.  Why  does  a  brisk  walk  or  a  horseback  ride  often  cure  one  of 
feeling  "out  of  sorts"? 


CHAPTER  X 

HOW  THE  BODY   SHOULD   BE   FED 
What  Shall  We  Eat? 

The  Choice  of  Food.  —  The  different  kinds  of  food 
have  been  considered  and  also  the  process  by  which  they 
are  digested  and  absorbed.  We  are  now  ready  to  take 
up  the  questions  we  all  have  been  asking  ourselves,  How 
can  I  improve  my  choice  of  food  and  my  habits  in  eating  ? 

To  let  taste  control  the  selection  of  food  is  foolish, 
unless  we  are  prepared  to  educate  our  taste  so  that  we 
shall  enjoy  all  wholesome  foods.  There  is  no  sensible 
reason  for  objecting  to  drinking  a  glass  of  milk,  or  to 
eating  a  dish  of  oatmeal ;  we  can  learn  to  enjoy  both  if 
we  will.  It  would  not  be  far  from  the  truth  if  we  were 
to  regard  every  wholesome,  digestible  dish  that  we  have 
not  learned  to  eat  as  one  count  against  us.  In  choosing 
our  food  there  are  a  few  actual  requirements  to  be  con- 
sidered. 

1.  We  must  have  some  proteins,  and  we  can  get  them 
from  meat,  eggs,  cheese,  beans,  bread,  and  many  other 
foods. 

2.  We  must  have  some  fuel  foods,  and  these  we  can 
get  best  from  the  grains,  from  some  vegetables,  and  from 
different  forms  of  fat. 

Digestibility  of  Foods.  —  Some  persons  see  better 
than  others  can ;  it  is  equally  true  that  some  digest  food 

70 


HOW  THE  BODY  SHOULD  BE  FED  71 

better  than  others  can.  Everybody  ought  to  know 
which  kinds  of  food  are  most  readily  digested.  One 
who  has  a  good  digestion  need  not  avoid  foods  that  are 
hard  to  digest  but  should  use  them  carefully,  not  taking 
too  much  of  such  food  at  one  meal.  One  whose  digestion 
is  not  so  good  shows  his  common  sense  in  living  prin- 
cipally on  food  that  is  easily  taken  care  of  by  the  digestive 
organs ;  in  that  way  he  may  often  greatly  improve  his 
digestion  and  so  be  able,  later,  to  eat  more  liberally  with 
entire  safety. 

Cheese,  for  example,  contains  a  very  large  amount  of 
valuable  food,  but  it  is  harder  to  digest  than  meat,  and 
is  therefore  less  useful.  If  cheese  is  eaten  in  small  quan- 
tities, and  with  other  food,  it  does  not  usually  trouble 
people  who  have  good  digestions.  If  eaten  in  large 
quantities  or  without  other  food,  the  digestive  organs 
have  difficulty  in  disposing  of  it  because  it  is  so  con- 
densed. Beans  are  very  nutritious;  people  in  good 
health  can  eat  them  in  moderate  quantities ;  those  who 
are  not  strong  and  those  who  lead  an  inactive  life  often 
have  difficulty  in  digesting  them. 

Circumstances  must  also  be  taken  into  account.  No  one 
can  derive  the  usual  amount  of  nourishment  from  food 
that  is  eaten  when  he  is  very  tired,  or  unhappy,  or  even 
when  he  is  too  busy  to  pay  attention  to  what  he  is  eating. 
When  such  times  come,  the  sensible  person  will  select 
food  that  is  easily  digested.  Those  who  are  living  or 
working  out  of  doors  can  eat  food  that  might  disagree 
with  them  if  they  were  leading  an  inactive  life  indoors. 

The  following  table  shows  some  of  the  more  easily 
digested  foods  and  some  of  those  less  easily  digested : 


72 


PHYSIOLOGY   AND   HEALTH 


FOODS  DIFFICULT  TO  DIGEST 
All  fried  foods 
Beans  and  peas 
Hard-boiled  eggs 
Pork 
Veal 
Cheese 
Nuts 


FOODS  EASY  TO  DIGEST 
Milk 
Bread 

Rice  and  other  cereals 
Soft-boiled  eggs 
Boiled  beef 
Fish 
Mutton 
Boiled  chicken 
Broiled  meats 
Potatoes 
Butter 


Methods  of  Cooking  Affect  Digestibility.  —  Foods  that 
are  boiled  or  broiled  are,  in  general,  more  quickly  digested 
than  those  that  are  roasted,  because  boiling  softens  the 
solids,  and  then  the  digestive  fluids  readily  act  upon 
them.  Fried  foods  are  the  most  difficult  to  digest, 


FIG.  22.  —  COOKED  AND  UNCOOKED  STARCH. 

The  figure  on  the  left  shows  about  fifteen  cells  filled  with 
starch  grains ;  and  that  on  the  right  shows  about  six  of 
the  cells  after  cooking. 

since  the  frying  is  apt  to  soak  the  food  with  fat,  which 
makes  it  difficult  for  the  digestive  juices  to  act  upon  it. 
There  are  a  few  vegetables,  like  lettuce  and  celery,  that 


HOW  THE  BODY  SHOULD  BE  FED  73 

we  eat  raw.  Most  vegetables  are  not  digestible  until 
they  are  cooked,  because  they  contain  starch  in  the  form 
of  hard  grains,  upon  which  the  digestive  juices  do  not 
easily  act.  Cooking  swells  these  grains  and  makes  them 
soft  and  easy  to  digest  (see  Figure  22). 

How  Much  Shall  We  Eat? 

Difficulty  of  Prescribing  a  Daily  Ration.  —  It  is  ad- 
mitted that  most  Americans  eat  altogether  too  much 
food.  Many  of  the  ailments  from  which  they  suffer 
can  be  relieved  by  giving  them  only  two-thirds  as  much 
food  as  they  are  accustomed  to  eat  and  increasing  the 
amount  of  time  that  they  spend  in  the  open  air.  It 
would  be  impossible,  however,  to  say  that  certain  classes 
of  people  ought  to  eat  every  day  so  many  ounces  of  this 
kind  of  food  and  so  many  ounces  of  another.  We  know 
that  what  counts  is  not  the  number  of  ounces  put  into 
the  stomach,  but  the  amount  of  digested  food  that  the 
blood  can  absorb  from  what  is  eaten ;  that  varies  with 
different  people.  Yet  there  are  certain  general  direc- 
tions that  can  be  given,  and  by  following  them  one  may 
expect  to  discover  for  himself  how  to  know  when  he  is 
eating  the  right  quantity  of  food. 

How  Food  Needs  Are  Determined.  —  Experiments 
prove  that  a  person  who  is  doing  even  a  moderate  amount 
of  muscular  work  needs  twice  as  much  food  as  the  person 
who  is  studying  or  leading  a  quiet  life.  Brain  work 
may  seem  to  be  as  hard  or  harder  than  physical  work, 
but  it  does  not  require  extra  food.  Students  should 
remember  this,  particularly  when  they  are  not  taking 
much  outdoor  exercise.  An  aged  person  needs  much  less 


74  PHYSIOLOGY   AND   HEALTH 

food  than  one  who  is  young.  The  young  need  plenty 
of  protein  foods ;  and  those  who  are  working  all  day 
with  their  muscles  need  such  foods  as  beans,  cheese, 
graham  bread,  and  fats,  like  salt  pork.  These  will  give 
them  energy  for  their  work. 

Many  interesting  facts  concerning  the  action  of  our 
bodies  have  been  learned  by  inclosing  a  man  in  a  large, 
perfectly  air-tight,  sealed  box  that  was  provided  with 
arrangements  for  furnishing  him  with  all  the  necessary 
oxygen,  food,  and  water.  The  amount  of  food  actually 
used  up  by  the  man's  body  can,  under  those  circumstances, 
be  accurately  determined.  It  is  found  that  the  amount 
of  food  he  uses  depends  upon  how  active  he  is.  When 
he  goes  to  sleep,  the  amount  of  food  he  uses  decreases 
greatly,  but  increases  again  as  soon  as  he  wakes.  A  famous 
bicycle  racer  was  once  placed  in  such  a  box  and  asked 
to  ride  upon  a  bicycle,  which  was  fastened  inside  the 
box  in  such  a  way  that  he  could  keep  turning  its  wheels 
although  it  would  not  move  along  the  floor.  When  he 
was  trying  to  make  this  bicycle  go  as  rapidly  as  if  he 
were  riding  a  race,  it  was  found  that  he  used  up  the  food 
in  his  body  about  six  times  as  fast  as  when  he  was  re- 
maining quiet. 

In  other  experiments  college  students  were  put  in  the 
box  and  were  given  a  hard  examination  paper  to  write. 
Although  they  thought  they  had  worked  very  hard,  the 
test  showed  that  they  had  not  been  using  any  more  food 
than  they  used  when  sitting  still.  Muscle  work  requires 
much  food ;  brain  work  does  not.  So  you  can  never  tell 
a  person  exactly  how  much  food  he  needs  to  eat  since 
that  differs  so  much  with  different  conditions  in  his  life. 


HOW  THE  BODY  SHOULD  BE  FED 


75 


The  Average  Daily  Need.  —  In  selecting  food  neces- 
sary to  give  us  energy  for  our  work,  we  cannot  judge  by 
bulk  alone ;  a  pound  of  bread  will  give  much  more 
strength  than  a  pound  of  oysters,  and  it  will  cost  much 
less  than  the  oysters.  It  is  important  to  know  from 


Bread 


FIG.  23.  —  A  DAY'S  RATION. 

This  figure  shows  the  amount  of  food  required  in  twenty-four  hours  by 
a  fulf-grown  man.  Bread,  one-half  a  five-cent  loaf.  Steak,  one-half  a 
pound. 

which  foods  we  derive  the  most  real  nourishment.  Study 
the  table  on  page  87. 

An  idea  as  to  the  amount  of  building  food  and  fuel 
food  needed  in  a  day  may  be  gained  from  Figure  23. 
It  represents  a  day's  ration,  i.e.  the  amount  needed  by 
an  ordinary  man  in  twenty-four  hours ;  a  child  would 
require  about  two-thirds  as  much.  Vegetables  and 
fruits  could  also  be  added  to  such  a  ration  to  advantage, 
especially  those  that  contain  little  nourishment  but  are 
useful  chiefly  because  of  their  juices. 

Variety  in  Food.  —  It  is  a  mistake  to  have  many 
different  kinds  of  food  at  one  meal ;  the  variety  of  flavors 
and  the  pleasurable  taste  of  one  dish  after  another,  often 
lead  us  to  eat  much  more  than  we  either  need  or  want. 


76  PHYSIOLOGY   AND    HEALTH 

Variety  in  food  is  desirable,  but  that  can  easily  be  se- 
cured by  varying  the  food  from  day  to  day.  A  heavy 
dinner,  with  several  meat  courses  and  highly  spiced 
entries,  is  not  nearly  so  wholesome  (nor  so  pleasurable) 
as  a  simple  dinner  consisting  of  meat  or  cheese,  potatoes, 
a  single  vegetable,  bread  and  butter  (with  milk  for  the 
children),  and  fresh  fruit  or  a  simple  pudding. 

The  food  eaten  by  families  with  small  incomes  is 
usually  more  wholesome  than  that  of  those  who  have 
plenty  of  money  to  spend.  The  latter  are  likely  to  make 
expensive  meats  the  principal  part  of  each  day's  diet, 
and  that  is  certainly  unhealthful.  It  is  a  real  misfortune 
to  be  able  to  buy  such  foods  and  not  to  know  better  than 
to  use  them.  Those  who  are  obliged  to  choose  inex- 
pensive food,  and  to  consider  how  they  can  get  the  most 
nourishment  at  the  lowest  cost,  generally  select  such 
foods  as  bread,  beans,  milk,  rice,  and  potatoes ;  these 
are  not  only  inexpensive  but  are  also  the  most  desirable 
foods  for  constant  use. 

Candy  as  a  Temptation  to  Overeating.  —  Sugar  is  a 
good  food,  yet  those  who  like  candy  are  constantly  being 
warned  that  it  is  unhealthful  to  eat  much  of  it.  This 
seems  contradictory,  but  there  are  good  reasons  for  the 
warning. 

1.  Candy  is  made  of  cane  sugar,  the  most  difficult 
sugar  to  digest. 

2.  Sugar  is  a  fuel  food  of  much  value  to  an  active 
person  who  is  using  up  a  great  deal  of  energy;    but  if 
eaten  in  any  quantity  by  a  person  who  is  not  active,  it 
makes  him  fat  and  sluggish. 

3.  We  usually  eat  candy,  not  because  we  are  hungry 


HOW  THE  BODY  SHOULD  BE  FED        77 

but  because  we  like  it.  The  result  is  that  when  we 
have  eaten  enough  to  give  us  all  the  fuel  food  we  need, 
we  have  seldom  satisfied  our  taste,  so  we  keep  on  eating 
candy  and  thus  create  an  oversupply  of  this  kind  of  food. 
4.  We  are  apt  to  eat  the  candy  between  meals  or  after 
eating  all  the  food  we  need  in  some  other  form. 

When  Shall  We 'Eat? 

Regularity  of  Meals.  —  It  makes  little  difference 
about  the  hours  selected  for  our  meals ;  but  it  is  of 
great  importance  that  meals  should  be  at  regular  hours. 
There  are  many  different  kinds  of  work  going  on  in  the 
body,  all  related  to  one  another  to  a  greater  or  less  extent, 
and  the  work  of  the  body  will  be  carried  out  better  if  all 
kinds  of  work  are  harmonized.  The  first  requisite  is 
that  meals  should  be  at  the  same  time  every  day.  In 
this  country  most  persons  eat  three  meals  a  day ;  in  other 
countries  five  meals  are  common ;  in  some  two  meals  are 
the  rule.  The  body  will  adjust  itself  perfectly  to  any 
of  these  plans,  if  people  recognize  that  they  need  a  cer- 
tain amount  of  food  each  day  and  eat  only  that  amount, 
whether  they  take  it  in  two  meals  or  in  five. 

This  does  not  mean  that  it  is  well  to  eat  three  regular 
meals,  and  then  candy  or  other  food  between  meals, 
morning  and  afternoon.  The  stomach  depends,  as  much 
as  you  do,  upon  having  regular  times  for  work  and  for 
rest.  Think  how  difficult  it  would  be  if  when  you  went 
to  school  in  the  morning  you  never  knew  whether,  when 
it  was  time  to  close  for  the  day,  the  teacher  might  not 
announce  that  there  would  be  an  extra  session  of  three 
or  four  hours.  That  is  the  way  we  treat  the  stomach 


78  PHYSIOLOGY   AND    HEALTH 

when  we  eat  "  between  meals."  Even  if  we  only  eat 
one  slice  of  bread  with  butter,  the  digestive  processes 
have  to  take  place  just  the  same  as  if  we  had  made  a 
whole  meal  of  bread  and  butter.  A  lunch  during  school 
hours  may  be  useful  for  those  children  who  for  any 
reason  have  an  insufficient  breakfast,  but  it  is  not  to  be 
recommended  for  those  who  eat  a  good  breakfast. 

A  Suggestion  for  Each  Meal.  —  Most  people  eat 
breakfast  shortly  after  rising;  it  should  not  be  a  hearty 
meal.  Fruit,  a  cereal,  and  bread  and  butter  make  a 
good  breakfast  for  those  who  are  not  doing  hard  muscular 
work ;  those  who  are  working  out  of  doors  may  want  to 
add  an  egg.  Milk,  cocoa,  or  chocolate  may  be  used,  but 
we  must  then  remember  that  they  are  all  foods ;  and  if 
we  take  them,  we  need  less  of  other  food.  Water  is  the 
best  drink .  for  young  people ;  they  should  not  drink 
coffee,  although  most  adults  can  drink  it  without  injury 
if  they  do  not  use  too  much. 

The  hearty  meal  should  be  in  the  middle  of  the  day  or 
at  the  end  of  the  day  —  preferably  at  the  time  when  a 
person  can  either  rest  directly  after  eating,  or  else  do 
only  light  work.  It  is  not  well  to  do  hard  muscular  work 
for  half  an  hour  after  a  hearty  meal,  for  that  work  will 
call  to  the  active  muscles  blood  that  is  needed  by  the 
digestive  organs,  and  so  will  interfere  with  rapid  diges- 
tion. Mental  work  interferes  less ;  but  the  meal  inter- 
feres with  the  mental  work,  for  everybody  knows  that  it 
is  difficult  to  study  hard  right  after  dinner.  The  stomach 
takes  the  blood  that  would  otherwise  be  used  by  the 
brain,  and  the  brain  cannot  work  as  well.  So  the  rule 
is  no  heavy  work,  muscular  or  mental,  directly  after 


HOW  THE  BODY  SHOULD  BE  FED        79 

dinner.     Do  athletes  ever  eat  just  before  going  into  a 
race? 

The  third  meal  of  the  day  should  be  a  simple  one, 
whether  it  comes  at  noon  or  at  night.  Bread  and  butter, 
or  macaroni,  or  rice,  make  the  best  foundation  for  this 
meal,  with  an  egg  if  one  is  not  taken  at  breakfast,  and 
some  stewed  fruit  or  a  custard.  It  is  not  well  to  form 
the  habit  of  taking  a  bedtime  lunch;  healthy  people 
are  much  better  off  without  it.  For  habitual  wake- 
fulness,  a  glass  of  hot  milk  on  retiring  is  an  excellent 
remedy. 

How  Shall  We  Eat? 

1.  Eat  slowly  and  be  sure  that  the  food  is  well  chewed 
before  it  is  swallowed. 

2.  Do  not  eat  between  meals ;  that  -is  a  severe  tax  on 
the  stomach,  as  it  keeps  the  glands  in  constant  action. 

3.  Do  not  eat  a  hearty  meal  when  either  very  warm 
or  very  tired.     Rest  a  little  first. 

4.  Do  no  hard  physical  work  for  at  least  half  an  hour 
after  a  hearty  meal.     This  is  the  stomach's  busiest  time. 
We  should  help  it  by  keeping  the  body  quiet. 

5.  Remember  that  the  person  who  lives  a  very  active 
life  can  best  digest  and  absorb  his  food.     If  you  live  a 
quiet  life,  you  need  less  food  than  if  you  were  doing  hard 
physical  work. 

6.  Drink  plenty  of  water.     Water  is  required  to  dis- 
solve the  food  in  the  intestine.     It  is  also  required  to 
keep  the  blood  in  proper  condition.     We  are  much  more 
likely  to  drink  too  little  water  than  too  much.     A  person 
needs  in  all  about  nine  glasses  of  water  every  day ;  the 


80  PHYSIOLOGY   AND   HEALTH 

food  he  eats  might  contain  from,  three  to  five  glasses. 
If  we  are  really  careful  to  masticate  our  food,  and  to 
drink  slowly,  we  shall  never  drink  too  much  water,  even 
if  we  drink  freely  during  a  meal.  Ice  water,  if  used  at 
all,  should  be  sipped  slowly,  so  that  as  it  passes  down 
the  throat  it  may  be  warmed.  Ice  water  in  large  quan- 
tities produces  a  shock  when  it  enters  the  stomach  and 
may  interfere  with  digestion. 

It  used  to  be  thought,  before  digestion  had  been 
studied  in  the  great  scientific  laboratories,  that  it  was 
well  for  people  to  take  wine  or  some  other  alcoholic 
drink  with  meals,  to  aid  •  digestion.  Now  it  has  been 
demonstrated  that  this  was  wholly  a  mistake ;  that  no 
healthy  person  should  use  alcohol  for  that  purpose; 
that  it  does  not  help  him  to  digest  his  food.  Those  who 
wish  to  be  strong  and  vigorous,  with  healthy  digestive 
organs,  had  better  let  alcoholic  drinks  entirely  alone. 
When  people  are  ill,  it  is  for  the  physician  to  direct  what 
they  should  do. 

QUESTIONS 

1.  Why  should  we  educate  our  taste  so  as  to  enjoy  all  kinds  of 
wholesome  foods  ? 

2.  Why  should  we  avoid  eating  large  amounts  of  foods  that  are 
difficult  to  digest? 

3.  Since  cheese  is  made  from  milk  why  is  it  not  as  good  a  food  for 
babies  ? 

4.  What  kind  of  employment  can  you  think  of  that  would  require 
a  large  amount  of  food  ?     What  kind  that  would  need  little  food  ? 

5.  Can  you  think  of  any  reason  why  a  child  may  need  almost  as 
much  food  as  a  man? 

6.  Can  you  give  any  reason  why  wealthy  people  are  more  likely 
to  suffer  from  indigestion  than  people  in  moderate  circumstances  ? 


HOW  THE  BODY   SHOULD   BE   FED  81 

7.  How  much  time  do  you  usually  spend  in  eating  your  breakfast? 
Is  this  enough? 

8.  What  is  the  objection  to  eating  between  meals?    Can  you  give 
any  reason  why  a  school  lunch  is  frequently  allowed  ? 

9.  Can  you  give  any  reason  why  the  hearty  meal  should  be  for 
most  people  at  the  close  of  the  day?     Why  not  just  before  going  to 
bed?    Why  should  not  breakfast  be  the  hearty  meal? 

10.  Have  you  ever  suffered  with  bad  dreams  after  eating  a  very 
hearty  supper? 

11.  Why  should  one  avoid  talking  about  unpleasant  subjects  while 
at  the  table  ? 

12.  Why  is  it  difficult  to  study  just  after  dinner? 

13.  What  are  your  favorite  dishes  ?     Have  you  ever  eaten  too  much 
of  any  one  of  them  ? 

14.  How  much  water  should  one  drink  during  the  day? 

15.  Give  reasons  why  you  should  not  eat  your  lunch  and  study  at 
the  same  time. 

16.  Why  should  candy  be  eaten  in  small  amounts? 

17.  Read  over  the  rules  for  eating  and  write  down  what  ones  you 
follow  and  what  ones  you  do  not  follow. 


CHAPTER  XI 
INTELLIGENT   COOKING 

Importance  of  Good  Cooking.  —  Most  of  the  food  we 
eat  is  cooked.  Cooking  may  either  spoil  food  or  greatly 
improve  it ;  good  cooking  enables  people  to  get  full  value 
from  the  food  they  eat.  There  are  many  ways  of  cooking, 
and  since  the  meals  for  a  family  are  usually  prepared  by 
one  person,  it  is  not  necessary  for  each  member  of  the 
family  to  know  how  to  make  all  kinds  of  dishes.  The 
principles  of  cooking  every  intelligent  person  ought  to 
understand.  Further  than  that,  every  boy  should  know 
how  to  cook  well  the  simple  foods  that  are  prepared  when 
camping  or  living  o.ut  of  doors.  Every  ambitious  girl, 
no  matter  what  her  circumstances  in  life  may  be,  ought 
to  learn  how  to  do,  and  do  well,  all  kinds  of  plain  cooking. 
Even  though  she  may  think  she  will  never  need  to  do 
cooking  in  her  own  home,  she  must  appreciate  that  she 
can  manage  a  household  to  better  advantage  if  she  knows 
how  to  buy  food  and  how  to  care  for  it,  how  it  should  be 
cooked  and  how  it  should  be  served.  Could  a  man 
manage  his  business  properly  if  he  were  ignorant  of  all 
its  details  ?  Yet  many  women  try  to  become  good  house^ 
keepers  without  knowing  thoroughly  the  details  of  each 
branch  of  work  that  is  done  in  their  households. 

Why  We  Cook  Food.  —  There  are  three  reasons  for 
cooking  food. 

82 


INTELLIGENT   COOKING  83 

1.  Cooking   removes   the   danger  from    parasites;    this 
applies  particularly  to  meats. 

2.  Cooking  develops  the  flavor  of  foods,  which  means  that 
we  enjoy  eating  them  more,  and  so  digest  them  better. 

3.  Cooking  makes  most  food  easier  to  digest;    this  is 
especially  true  of  all  starchy  foods. 

In  general,  food  is  cooked  in  order  to  improve  it ;  so 
one  of  the  first  problems  in  cooking  is  to  learn  how  to 
apply  heat  to  different  kinds  of  food  in  the  way  that 
shall  improve  them  most.  Fats  are  melted  or  made 
softer  when  heated.  Heat  swells  the  grains  of  starch 
and  causes  them  to  soften,  so  that  they  are  more  easily 
digested  (see  Figure  22).  It  has  an  opposite  effect  on 
meat  and  eggs ;  they  are  hardened  by  heat,  as  are  most 
other  proteins,  and  they  are  therefore  more  difficult  to 
digest  after  cooking.  The  reason  for  cooking  them  is 
because  most  people  enjoy  their  flavor  better  after  they 
are  cooked.  With  meat  there  is  an  additional  reason ; 
raw  meat  is  less  safe  than  cooked  meat  because  of  the 
parasites  that  may  be  in  it.  With  proteins,  therefore, 
one  problem  is  to  cook  them  in  such  ways  that  the  heat 
used  shall  not  harden  them  too  much. 

Three  Different  Ways  of  Cooking.  —  In  a  cookbook 
there  are  hundreds  of  recipes  for  preparing  food.  When 
it  is  ready  for  cooking,  there  are  only  three  ways  in  which 
the  cooking  is  done :  boiling,  baking,  frying.  Potatoes 
may  be  cooked  in  any  one  of  these  ways,  and  the  use  of 
different  methods  at  different  times  gives  the  needed 
variety.  In  cooking  protein  food,  we  have  to  consider 
more  than  how  to  secure  variety.  Sometimes  we  want  to 
keep  the  rich,  nutritious  part  of  the  meat  inside  of  it ; 


84  PHYSIOLOGY   AND   HEALTH 

sometimes  we  want  to  let  the  nutriment  out  into  the 
liquids  in  which  the  meat  is  being  cooked.  We  have  to 
proceed  differently  in  the  two  cases. 

To  keep  the  richness  in  the  meat  itself,  we  apply  a 
considerable  degree  of  heat  to  the  outside  of  the  piece 
of  meat,  heating  it  quickly  so  that  the  surface  will  be 
seared,  forming  a  crust  that  will  hold  the  juices  within. 
To  draw  the  richness  out  of  the  meat  and  into  the  juice, 
we  heat  it  very,  very  slowly,  allowing  no  crust  to  form. 

Baking.  —  Cooking  food  in  hot  air,  we  call  baking, 
roasting,  or  broiling,  depending  upon  the  manner  in 
which  the  hot  air  is  applied.  If  it  is  desired,  as  with 
meat,  to  form  a  crust  quickly,  then  the  food  should  be 
put  into  a  hot  oven,  and  the  heat  gradually  decreased. 
Some  of  the  flavor  and  richness  of  the  meat  will  escape 
through  the  crust,  but  much  of  this  can  be  preserved  by 
basting  the  meat  every  fifteen  minutes ;  that  is,  pouring 
over  it  the  liquids  that  have  escaped  into  the  baking  pan. 
When  there  is  no  occasion  to  form  a  crust,  even  heat  is 
the  best,  with  extra  heat  at  the  end  if  it  is  desired  to 
brown  the  top  of  the  dish. 

Broiling  means  cooking  over  a  very  hot  fire.  It  is 
really  a  form  of  baking.  We  usually  speak  of  broiling 
meat ;  the  toasting  of  bread  is  also  a  form  of  broiling. 
When  broiling  meat,  it  is  important  to  prepare  in  ad- 
vance a  hot  bed  of  coals  (or  in  a  gas  range,  a  well-heated 
broiler),  so  that  the  outside  of  the  meat  may  be  quickly 
seared  over  and  the  juices  kept  in  it,  instead  of  escaping 
on  to  the  coals. 

Boiling.  —  When  food  is  cooked  in  boiling  water,  we 
call  the  process  boiling.  If  the  goodness  is  to  be  kept 


INTELLIGENT   COOKING  85 

within  the  food,  we  put  it  into  water  that  is  actually 
boiling.  To  extract  the  goodness,  we  put  the  food  into 
cold  water,  and  let  the  water  come  to  a  boil  so  gradually 
that  the  strength  of  the  food  has  a  chance  to  soak  out 
before  the  boiling  begins.  If  the  liquid  in  which  your 
mutton  was  boiled  tastes  rich  enough  to  make  good  soup, 
then  there  was  a  mistake  in  the  beginning,  —  too  much  of 
the  flavor  of  the  meat  was  allowed  to  escape  into  the 
liquid.  Vegetables,  too,  should  be  dropped  into  boiling 
water,  so  that  the  flavors  may  not  be  soaked  out  of  them 
in  the  process  of  cooking  and  be  lost  when  the  water  in 
which  they  were  boiled  is  thrown  away. 

In  making  a  soup,  we  usually  desire  to  extract  the  flavor 
from  the  meat  and  the  vegetables.  So  both  meat  and 
vegetables  should  be  cut  up  into  small  pieces  and  put 
into  the  soup  kettle  with  cold  water.  The  kettle  is  set 
back  on  the  stove  and  is  gradually  heated ;  if  it  simmers 
for  hours,  without  boiling,  the  flavor  of  the  soup  will  be 
better.  Even  with  all  this  care,  much  of  the  value  of  the 
meat  remains  in  the  me.at  itself.  For  that  reason  clear 
soups,  from  which  the  meat  has  been  strained,  have  little 
food  value ;  they  are  regarded  as  good  "  appetizers " 
with  which  to  begin  a  dinner. 

In  stews,  the  meat  and  the  vegetables  are  served  with 
the  broth ;  then  we  get  the  whole  goodness  of  them  — 
the  flavors  in  the  broth  and  in  the  meat,  and  the  pro- 
teins which  were  coagulated  by  the  heat  and  would  not 
soak  out  into  the  broth.  Stews  are  therefore  very  nutri- 
tious. 

Frying.  —  We  fry  foods  by  dropping  them  into  fat 
which  has  been  heated  very  hot.  Foods  cooked  in  this 


86  PHYSIOLOGY   AND   HEALTH 

way  are  coated  with  a  hard,  fat-soaked  crust  which 
renders  them  difficult  of  digestion.  '  •  v  *  ... .. 

Beef  Tea.  —  Often  it  is  desired  to  extract  the  nourish- 
ment from  a  piece  of  beef  for  an  invalid  who  is  not  able 
to  eat  the  meat,  no  matter  how  carefully  it  may  be 
cooked.  A  common  method  is  to  make  beef  tea ;  it  has  a 
delicious  odor  and  taste,  but  if  made  in  the  ordinary  way 
it  has  little  to  recommend  it  except  its  flavor.  When 
the  beef  is  cut  into  very  small  pieces  and  put  to  soak  in 
cold  water,  a  part  of  the  nutritious  protein -material  will 
be  extracted;  but  if  the  liquid  is  allowed  to  come  to  a 
boil,  the  protein  will  at  once  coagulate  and  appear  in  a 
brownish  skum.  When  we  strain  that  off,  we  remove 
almost  all  the  nutriment  the  liquid  contains.  If  the 
liquid  were  only  slightly  warmed  so  as  not  to  coagulate 
the  protein, .it  would  still  contain  nutriment;  but  if  it  is 
boiled  and  strained,  no  real  food  is  left  in  it. 

"  Raising."  —  Meat  and  vegetames  require  little' prep- 
aration previous  to  cooking,  and  the  same  is  true  of  the 
grains  when  used  as  cereals.  But  it  is  different  with  the 
making  of  bread,  muffins,  cake,  pies,  and  the  many  other 
foods  of  that  general  sort.  Flour  is  seldom  used  without 
some  form  of  "  raising  "  material  to  make  the  batter 
"  light,"  yeast  or  baking  powder  being  generally  used. 

When  bread  is  made,  yeast  is  added  to  the  dough  and 
the  mixture  is  put  into  a  warm  place  to  "•  rise  "  for  several 
hours ;  that  is,  to  allow  the  yeast  plants  to  grow  in  the 
mixture.  As  they  grow  they  produce  a  gas  called  carbon 
dioxid  and  a  very  small  amount  of  alcohol ;  the  bubbles 
of  the  gas  make  the  mixture  swell  as  they  try  to  escape 
from  it.  The  "  raising  "  must  be  stopped  at  the  right 


INTELLIGENT   COOKING 


87 


Cheese 

Peanuts 

Leg  of  Mutton 

Dried  Peas 

Dried  Beans 

Roast  Beef 

Canned  Salmon 

Chicken 

Veal 

Almonds 

Brazil  Nuts 

Soft-shell  Walnuts 

Oatmeal 

Wheat  Flour 

Egg 

Macaroni 

Oyster  Crackers 

Bread 

Rice 

Green  Peas 

Sponge  Cake 

Fresh  Oysters 

Gingerbread 

Squash  Pie 

Tapioca  Pudding 

Milk 

Apple  Pie 

Green  Corn 

Potatoes 

Dried  Prunes 

Fresh  Asparagus 

Cabbage 

Bananas 

Butter 

Fresh  Tomatoes 

Fresh  Cranberries 


FIG.  24.  —  A  table  showing  percentages  of  different  food  substances  present  in 
ordinary  foods,  arranged  according  to  the  amount  of  protein  they  contain.   , 


88  PHYSIOLOGY   AND    HEALTH 

time  or  else  the  mixture  will  sour.  It  is  stopped  by 
putting  the  loaves  into  the  oven,  the  heat  then  killing  the 
yeast  and  driving  off  both  alcohol  and  gas.  No  trace  of 
the  alcohol  is  left ;  but  the  gas  leaves  its  traces  in  the 
small  holes  all  through  the  loaf  which  were  full  of  gas 
when  the  loaf  went  into  the  oven.  Their  presence  makes 
the  bread  "  light/'  easier  to  masticate  and  to  digest. 

Baking  powder  acts  in  much  the  same  way  as  yeast; 
it  is  a  more  expensive  method  of  raising  dough,  but  it 
works  immediately.  So  it  is  often  more  convenient  to 
use  baking  powder,  and  less  skill  is  required  for  its  use. 
The  flavor  of  food  raised  by  baking  powder  is  quite 
different  from  that  of  food  raised  by  yeast. 

QUESTIONS 

1.  Give  three  reasons  for  cooking  food.    Which  of  these  reasons 
applies  most  to  the  cooking  of  potatoes?    Meats?    Eggs? 

2.  Why  is  it  important  that  every  one  understand  the  principles 
of  cooking? 

3.  What  advantage  is  there  in  having  food  well  flavored? 

4.  Why  should  one  give  careful  attention  to  the  temperature  of 
the  oven  before  putting  meat  in  to  roast? 

5.  Which  will  keep  the  more  food  value  in  a  piece  of  meat  —  baking 
or  boiling?     Why? 

6.  Why  is  beef  stew  an  especially  nutritious  dish?    Find  out  the 
average  cost  of  meat  suitable  for  a  stew.     Compare  this  with  the  cost 
of  porterhouse  steak  or  mutton  chop. 

7.  Why  is  it  that  beef  tea,  although  it  is  made  of  meat,  has  prac- 
tically no  value  as  a  food? 

8.  What  objection  is  there  to  frying  food? 

9.  How  many  ways  do  you  know  of  cooking  eggs?    Which  do  you 
think  makes  them  most  digestible? 

10.  What  kind  of  bread  do  you  think  could  be  made  if  neither  yeast 
nor  baking  powder  were  put  in  the  dough? 


CHAPTER  XII 
INTELLIGENT   FIGHTING   OF   THE   BODY'S   FOES 

The  Body  Its  Own  Hospital.  —  The  body  has  to  contend 
constantly  with  our  carelessness ;  we  eat  the  wrong  food 
or  we  eat  at  the  wrong  time,  and  get  sick  stomachs. 
Then  accidents  happen  which  we  could  not  prevent  — 
a  bone  is  broken  by  a  fall,  or  some  part  is  wounded,  or 
we  "  catch  cold."  The  body,  if  properly  cared  for,  is 
able  to  deal  with  all  these  difficulties ;  slight  illnesses  are 
soon  righted,  broken  bones  are  mended,  and  even  deep 
wounds  heal  in  a  short  time.  In  fact  the  most  wonderful 
hospital  in  the  world  is  the  one  that  the  body  itself  con-' 
ducts ;  small  disorders  are  set  right  in  the  body  without 
our  ever  being  conscious  of  them  at  all ;  ordinary  illnesses 
are  cured  without  even  making  it  necessary  for  us  to 
stay  in  bed. 

Drugs  Do  not  Cure  Disease.  —  When  the  disorder  is 
one  that  is  not  quickly  righted,  we  say  that  the  person 
is  ill,  or  has  some  disease.  If  the  illness  is  serious,  a  doctor 
is  summoned ;  if  it  does  not  seem  serious,  many  people 
begin  to  take  some  medicine  which  their  friends  may 
recommend  to  "  cure  "  the  illness.  But  medicines  do 
not  cure  diseases ;  at  best  they  can  only  help  the  body 
to  right  itself.  Under  ordinary  circumstances,  the  best 
way  to  help  the  body  is  to  find  out  what  wrong  habit  or 
what  carelessness  is  causing  the  trouble  —  and  stop  it. 

89 


90  PHYSIOLOGY   AND    HEALTH 

A  few  simple  remedies  like  hot  baths,  change  of  food, 
extra  exercise  in  the  open  air,  and  other  things  that  will 
be  mentioned  in  this  book  are  much  better  aids  to  the 
body  than  drugs.  If  medicines  are  needed,  they  should 
be  taken  under  the  direction  of  a  physician.  What  does 
a  physician  do  when  he  is  sick  himself?  He  does  not 
begin  taking  drugs ;  he  sends  for  another  doctor,  tells 
him  about  the  illness,  and  takes  such  medicine  as  the 
doctor  prescribes.  He  knows  that  a  sick  person  is  not 
a  good  judge  of  what  he  needs. 

The  Patent  Medicine  Folly.  —  It  is  estimated  that 
over  $50,000,000  are  spent  in  this  country  every  year 
for  "  patent  medicines  "  ;  that  is,  for  prepared  drugs  that 
people  buy  to  "  cure  "  some  disease  or  other.  This  is  a 
very  expensive  way  of  buying  medicine ;  in  many  cases 
a  "  dollar  bottle  "  contains  only  a  few  cents'  worth  of 
drugs.  Many  patent  medicines  may  be  harmless;  but 
others  are  most  injurious  and  their  use  is  worse  than 
foolish.  If  you  find  that  the  lamp  on  your  table  is 
going  out,  you  do  not  run  for  matches  and  keep  trying 
to  relight  it.  You  investigate  to  see  whether  the  oil  has 
burned  out  or  whether  the  wick  is  too  short  to  reach  the 
oil ;  that  is,  you  find  the  cause  of  the  difficulty  and  re- 
move it.  One's  body  is  worth  as  much  care  as  a  lamp ; 
and  it  is  much  better  to  discover  what  is  wrong  with  it 
than  to  run  to  the  drug  store  with  a  dollar  bill  for  some 
patent  medicine  that  cannot  "  cure  "  the  trouble,  and 
may  make  it  much  worse. 

The  Body's  Worst  Enemies.  —  In  our  battle  to  keep 
well  and  strong  there  are  certain  diseases  that  we  have 
to  fight ;  to  understand  about  them  it  is  necessary  to 


INTELLIGENT   FIGHTING  OF   THE   BODY'S   FOES     91 


know  something  of  what  has  been  discovered  in  the  last 
fifty  years  about  the  worst  enemies  of  the  body.  These 
are  tiny  animals  and  plants,  many  of  them  too  small  to 
be  seen  with  the  ordinary  microscope ;  they  get  into  our 
bodies  and  grow  there,  the  result  being  that  we  are  ill, 
perhaps  very  ill.  When  any  living  thing  lives  in  and 
feeds  upon  another,  we  call  it  a  parasite ;  and  these 
plants  and  animals  that  cause  disease  are  also  parasites. 
Mention  has  been  made  of  the  Trichina  and  the  tape- 
worm, parasites  which  may  make  trouble  in  the  intestines  ; 
but  more  important  than  these  are  microscopic  plants 
called  bacteria. 

We  have  already 
found  that  bacteria 
may  live  in  milk  and 
also  float  about  freely 
in  the  air,  ready  to 
fall  into  our  food. 
Are  they  alt  enemies? 

Indeed    they  are  not.      FIG.   25. —BACTERIA   AND   THE    POINT  OF  A 

Many    bacteria    are  CAMBRIC  NEEDLE. 

really     our     good 

friends  and  do  much 

useful    work   for   us. 

But    other   kinds    of 

bacteria  are  our  worst 

enemies ;     these    are 

called  germs,  and  the  diseases  they  produce  are  called 

germ  diseases. 

Every  germ  disease  is  produced  by  a  special  germ  which 
causes  that  disease  and  no  other.     Some  of  them  are 


The  figure  shows  the  comparative  sizes.  The 
minute  dots  at  the  end  of  the  needle  repre- 
sent the  size  of  the  bacteria.  The  others 
arranged  around  the  needle  are  bacteria  more 
highly  magnified.  The  sources  of  the  latter 
are  :  a,  typhoid  fever ;  6,  diphtheria ;  c,  boils 
or  abscesses ;  d,  tuberculosis ;  e,  sour  milk ; 
/,  grip. 


92  PHYSIOLOGY   AND   HEALTH 

dangerous  only  to  the  person  whose  body  is  attacked  by 
the  germ.  But  there  are  others  that  are  likely  to  pass 
from  the  sick  person  to  the  well  people  around  him,  and 
we  call  the  diseases  they  produce  contagious  diseases. 
When  a  child  in  the  family  has  the  germ  disease  called 
malaria,  there  is  no  more  reason  to  fear  that  the  other 
members  of  the  family  will  take  malaria  from  him  than 
there  is  that  they  would  break  their  arms  if  he  broke 
his  arms.  Malaria  is  not  contagious;  but  if  a  child 
has  measles,  the  other  children  in  the  family  would  be 
likely  to  "  catch  "  the  disease  from  him.  All  diseases 
caused  by  germs  are  called  infectious,  but  not  all  of  them 
are  contagious. 

Until  recent  years,  no  one  knew  how  certain  diseases 
passed  from  one  person  to  another ;  the  result  was  that 
one  sick  person  often  gave  a  contagious  disease  to  hun- 
dreds of  others,  without  anybody's  knowing  how  to  pre- 
vent it.  Now  most  contagious  diseases  can  be  checked 
before  they  spread  through  the  community  if  every  one 
will  take  the  precautions  that  have  been  discovered  to 
be  necessary. 

How  the  Body  Is  Protected.  —  Disease  germs  are 
mostly  short  lived.  To  be  sure  there  are  countless  millions 
of  them,  but  most  disease  germs  live  only  a  few  weeks 
unless  they  can  find  entrance  into  the  body  of  a  human 
being  or  an  animal  and  begin  to  grow  there.  Fortunately 
for  us  there  are  not  many  ways  in  which  they  can  enter 
our  bodies.  The  body  is  covered  with  skin,  which  to  a 
little  germ  is  thicker  and  firmer  than  a  stone  wall ;  unless 
there  is  some  break  in  it  (like  a  loose  stone  in  a  wall)  the 
germs  are  barred  out  by  one's  skin.  When  the  skin  is 


INTELLIGENT  FIGHTING  OF  THE  BODY'S  FOES     93 

whole,  about  the  only  ways  open  to  germs  are  to  get  in 
with  the  air  we  breathe,  or  with  our  food  and  drink. 

When  they  once  have  found  their  way  into  the  nose 
or  the  mouth,  they  can  easily  get  into  the  stomach  or 
the  lungs.  But  even  then  it  is  more  than  likely  that  the 
body  will  be  able  to  destroy  them  before  they  do  any 
harm.  A  robust  body  has  great  power  to  resist  the 
attack  of  disease  germs,  for  it  can  frequently  prevent 
their  having  any  chance  to  grow  even  if  they  do  find  an 
entrance.  So  the  first  and  best  precaution  against  these 
tiny  enemies  is  to  keep  in  good  physical  condition ; 
that  we  can  do  by  eating  plain  wholesome  food  and 
following  the  other  rules  of  health  that  most  of  us  know 
but  are  too  apt  to  forget. 

Germ  Diseases  in  the  Digestive  Organs 

It  is  not  important  for  people  to  know  about  the  diseases 
that  they  cannot  avoid  taking.  If  such  a  disease  comes, 
we  send  for  the  doctor  and  do  whatever  he  tells  us  will 
help  the  body  to  fight  against  it.  We  are  not  studying 
diseases  in  this  book  —  it  is  enough  for  doctors  to  know 
all  about  them.  What  we  want  to  know  is  how  to  keep 
well  and  how  to  avoid  those  diseases  that  may  be  avoided. 

There  are  three  diseases  of  the  digestive  organs  about 
which  everybody  should  know,  because  they  are  common, 
serious,  and  preventable.  One  ought  to  understand  both 
how  to  guard  against  having  them,  and  how  to  prevent 
giving  them  to  others  if  he  chances  to  be  taken  with  one 
of  them  himself.  These  three  diseases  could  be  com- 
pletely stamped  out  if  it  were  only  possible  to  prevent, 


94  PHYSIOLOGY   AND   HEALTH 

for  one  year,  the  existence  of  a  single  case.  Then  we 
should  probably  never  hear  of  them  again,  except  as 
strange  disorders  that  used  to  prevail  before  people 
took  the  trouble  necessary  to  get  rid  of  them.  Those 
three  diseases  are  typhoid  fever,  hookworm,  cholera. 

Typhoid  Fever.  —  No  one  ever  has  typhoid  fever  unless 
a  special  kind  of  germ  that  causes  it  gets  into  the  intes- 
tines, and  is  able  to  overcome  there  the  resistance  of  the 
body  (Figure  25) .  If  the  germ  gets  a  start,  it  grows  rapidly 
in  the  intestines  and  produces  an  immense  number  of  germs 
like  itself  which  work  serious  mischief.  The  germs  pass 
from  the  body  in  the  feces  and  in  the  urine ;  they  are  not 
dead,  but  are  ready  to  do  the  same  work  in  the  body  of 
some  one  else.  They  can  remain  alive  for  about  six  weeks ; 
then,  if  they  do  not  find  their  way  into  the  body  of  another 
person,  they  die.  Since  there  is  no  danger  of  taking  them 
from  the  sick  person's  breath,  one  might  imagine  that  it 
would  not  be  difficult  to  take  such  care  of  the  discharges 
from  the  patient  as  to  protect  other  people.  But  the  fact 
that  we  cannot  see  the  germs  makes  it  much  more  difficult 
to  avoid  contact  with  them.  They  are  commonly  carried 
to  well  people  in  four  ways. 

In  Drinking  Water.  —  How  could  excretions  from  a 
person  sick  with  typhoid  fever  get  into  drinking  water? 
Through  carelessness  on  the  part  of  those  who  take  care 
of  the  sick  person  the  excretions  may  be  thrown  on  to 
the  ground  and  from  there  washed  into  a  well.  A  crack 
in  the  floor  of  a  well  house  may  be  more  dangerous  to 
a  community  than  a  mad  dog.  When  the  excretions 
are  put  into  water-closets,  they  pass  from  there  into  the 
sewers  in  the  streets  and  through  the  sewers  into  some 


INTELLIGENT   FIGHTING  OF  THE  BODY'S   FOES     95 

stream  of  water.  If  the  people  who  live  a  few  miles 
further  down  the  river  take  their  drinking  water  from  it, 
they  are  likely  to  keep  having  cases  of  typhoid  fever. 
Any  stream  into  which  sewage  is  emptied  is  unsafe  as  a 
source  of  drinking  water.  There  are  three  things  that 
may  be  done :  either  find  some  other  way  of  disposing 
of  the  sewage,  or  find  some  safe  source  from  which  the 
drinking  water  can  be  taken,  or  use  some  method  of  purify- 
ing the  water.  Until  one  of  these  safeguards  has  been  put 
into  operation  the  citizens  should,  for  safety,  boil  all  their 
drinking  water,  and  thus  kill  any  typhoid  germs. 

In  Milk.  —  Typhoid  germs  are  occasionally  found  in 
milk,  and  yet  the  disease  germs  do  not  come  from  the  milk 
itself.  If  the  milkman  washes  his  cans  in  water  that,  with- 
out his  knowing  it,  contains  typhoid  germs,  they  may  get 
into  the  can  and  so  into  the  milk.  Sometimes  they  are 
communicated  to  milk  from  the  handling  of  the  milk  re- 
ceptacles by  a  milker  who  is  recovering  from  the  disease. 
Sometimes  people  who  have  recovered  entirely  from  the 
disease,  or  may  never  have  had  it,  carry  the  germs  around 
in  their  bodies  for  a  long  time.  They  are  called  "  typhoid 
carriers,"  and  it  is  dangerous  to  have  them  work  in  a  dairy. 
This  may  seem  a  fantastic  account  of  the  way  typhoid 
fever  is  spread,  but  many  instances  are  known  in  which 
one  case,  improperly  cared  for,  has  resulted  in  many 
others. 

A  typical  instance  occurred  in  a  small  city  where  some 
forty  people  were  taken  ill  with  this  disease  at  about  the 
same  time.  Several  died,  and  for  weeks  the  others  were 
very  seriously  ill.  It  was  found  that  all  the  sick  people 
had  been  using  milk  from  a  certain  dairy.  An  inspection 


96 


PHYSIOLOGY  AND   HEALTH 


of  this  dairy  disclosed  the  fact  that  about  two  weeks 
before  the  typhoid  cases  started  a  "  typhoid  carrier  " 
had  been  employed  in  the  dairy.  Without  knowing  it, 
he  had  communicated  typhoid  germs  to  the  milk  he  was 
handling,  and  those  who  drank  the  milk  suffered. 

By  House  Flies.  —  Flies  always  congregate  in  foul 
places ;  if  they  happen  to  feed  on  the  feces  of  typhoid 
fever  patients,  the  fever  germs  may  adhere  to  their  feet, 
and  then  they  may  carry  those  germs  into  the  kitchens 
where  food  is  being  prepared,  and  leave  them  on  the  food 
that  is  soon  to  be  eaten.  Flies  look  harmless,  but  they 
are  not.  There  ought  to  be  a  general  movement  all  over 
the  country  to  kill  the  flies. 

In  some  places,  the  house  fly  is  called  the  "  typhoid  fly," 
as  a  reminder  of  the  danger  from  it.  The  best  way  to 


FIG.  26.  —  A  HOUSE  FLY. 
The  eggs,  two  stages  of  the  young,  and  the  adult  are  shown. 

exterminate  flies  is  to  destroy  their  breeding  places,  at 
the  same  time  killing  those  that  get  into  the  house. 


INTELLIGENT   FIGHTING  OF  THE  BODY'S  FOES     97 

Flies  lay  their  eggs  in  garbage  cans,  manure  heaps,  or 
other  decaying  masses.  Thousands  of  flies  may  thus 
come  from  a  single  garbage  can,  for  flies  multiply  very 
rapidly.  A  single  fly  if  it  has  plenty  of  garbage  to  breed 
in  may  produce  25,000,000  others  in  30  days.  By  spend- 
ing a  few  moments  in  keeping  garbage  cans  tightly  covered 
so  that  flies  cannot  get  into  them  to  lay  their  eggs  we  can 
do  much  more  toward  reducing  the  numbers  of  flies  than 
we  could  by  going  around  all  day  "  swatting  the  fly/' 
The  fight  against  the  fly  is  a  fight  for  health.  Filth  and 
health  never  make  good  bedfellows. 

By  Oysters  and  Shellfish.  —  If  oysters  and  clams  grow 
in  water  near  the  outlet  of  sewers,  they  may  become  con- 
taminated with  the  typhoid  germs ;  when  they  are  eaten 
raw,  the  living  germs  may  be  taken  into  the  stomach. 
The  danger  is  greatest  in  the  fall  months ;  in  winter,  raw 
oysters  are  seldom  if  ever  infected.  When  oysters  are 
cooked,  there  is  no  danger  from  them  at  any  season. 

Here  is  a  well-authenticated  instance  of  the  danger  from 
eating  raw  oysters.  There  was  a  typhoid  fever  case  near 
the  seashore,  and  the  excretions  were  thrown  into  a 
sewer.  The  discharge  from  the  sewer  floated  over  to 
oysters  that  were  in  the  water,  not  far  from  the  sewer. 
Later  these  oysters  were  sold  in  a  neighboring  city,  and 
one  evening  about  a  hundred  college  students  ate  some  of 
these  oysters.  Forty  students  were  taken  with  typhoid 
fever,  four  of  them  died,  and  the  others  recovered  after 
being  ill  for  many  weeks. 

Hookworm  Disease.  —  There  is  a  disease  very  common 
in  certain  parts  of  our  country  called  the  hookworm 
disease.  It  is  widely  prevalent  in  the  southern  states, 


98  PHYSIOLOGY   AND   HEALTH 

and  uncommon  in  the  north.  It  is  a  strange  disease,  for 
the  patient  frequently  does  not  realize  that  he  is  ill. 
He  feels  weak  and  indolent,  and  perhaps  he  agrees  with 
his  friends  when  they  call  him  lazy ;  but  he  is  really  sick. 
In  many  cases  the  disease  is  serious ;  it  prevents  the 
growth  of  children  and  makes  them  so  stupid  that  they 
appear  only  half-witted.  A  man  with  hookworm  is 
about  as  efficient  as  if  his  right  hand  were  tied.  It 
spoils  the  lives  of  many  people.  Fortunately  men  have 
learned  how  both  to  prevent  and  to  cure  it. 

The  cure  of  the  disease  must  be  left  to  the  physician. 
But  the  prevention  is  simple.  The  disease  is  caused  by 
tiny  worms  that  live  in  the  intestines,  sometimes  in 
great  numbers.  These  tiny  worms  produce  many  eggs 
which  pass  out  of  the  intestine  in  the  feces  and  then 
develop  into  little  worms,  too  small  to  be  seen  by  the  eye. 
When,  through  careless  disposition  of  the  feces,  these 
worms  get  into  the  ground,  they  may  remain  alive  there 
for  a  long  time.  Then  if  a  person  happens  to  walk  over 
the  ground  barefooted,  the  worms  may  attach  them- 
selves to  his  feet  and  cling  to  them.  They  proceed  to 
bore  their  way  through  his  skin  and  finally  make  their 
way  into  the  blood  vessels.  They  are  carried  around 
the  body  in  the  blood  and  at  last  may  enter  the  intestine, 
where  they  soon  give  rise  to  the  disease.  Perhaps  there 
are  some  other  methods  by  which  they  may  be  communi- 
cated to  the  body,  but  this  seems  to  be  the  most  impor- 
tant. 

It  will  thus  be  seen  that  the  disease  is  spread  by  filthy 
habits ;  is  acquired  by  going  barefooted ;  and  may  be 
largely  avoided  by  wearing  shoes.  An  active  campaign 


INTELLIGENT   FIGHTING  OF   THE   BODY'S   FOES     99 

carried  out  in  the  states  that  are  most  affected  has  largely 
reduced  the  disease. 

HEALTH   NOTES 

Disease  germs  that  are  dangerous  to  human  beings  are  more 
likely  to  be  found  in  excretions  from  the  human  body  than  in  any 
other  substance.  For  this  reason  there  is  the  greatest  need  that 
proper  disposition  should  be  made  of  the  excretions.  We  have 
learned  that  typhoid  bacteria  and  the  eggs  of  the  hookworm  may 
be  in  the  feces,  and  the  germs  of  tuberculosis,  as  well  as  other 
dangerous  germs,  are  also  sure  to  be  in  these  and  other  excretions. 
Hence  great  care  is  necessary  not  only  in  disposing  of  sewage  but 
to  make  certain  that  toilets  do  not  become  a  source  of  infection. 
Where  toilets  have  connections  with  sewers  they  should  be  flushed 
with  water  every  time  that  they  are  used,  and  the  greatest  care 
should  be  taken  to  keep  the  bowls  of  them  absolutely  clean. 

Where  the  old-fashioned  privy  is  in  use,  it  must  be  so  covered 
that  flies  cannot  reach  the  excretions,  for  they  not  only  find  this 
their  favorite  place  for  laying  their  eggs,  but  they  feed  upon  the 
filth,  and  then  fly  into  the  house,  where  they  may  light  on  food  or 
on  baby's  milk  bottle,  leaving  dangerous  disease  germs  that  have 
become  entangled  in  the  hairs  on  their  feet. 

QUESTIONS 

1.  Why  should  one  avoid  taking  medicine  except  under  the  direc- 
tion of  a  physician? 

2.  Have  you  ever  noticed  "patent  medicine"  advertisements  in 
the  newspapers?     Can  these  medicines  cure  the  diseases  which  they 
claim  to? 

3.  Find  out  if  you  can  some  of  the  harmful  ingredients  which  are 
occasionally  found  in  patent  medicines  —  headache  tablets,  catarrh 
cures,  etc. 

4.  What  are  parasites?     Are  all  disease  germs  parasites? 

5.  Can  you  explain  why  a  cut  or  bruise  should  be  washed  with  clean 
water? 


100  PHYSIOLOGY  AND   HEALTH 

6.  What  precautions  can  one  take  to  avoid  typhoid  fever? 

7.  What  is  the  best  way  of  caring  for  garbage  in  the  country? 
In  the  city  ?     How  should  the  garbage  can  be  cared  for  ? 

8.  Can  you  think  of  any  reasons  why  it  is  the  duty  of  every  one  to 
help  keep  the  streets  clean? 

9.  What  dangers  are  apt  to  result  if  one  allows  the  soil  around  one's 
house  to  become  filled  with  pollution  ?     Should  there  be  a  law  pre- 
venting this? 

10.  Are  there  any  places  near  your  home  which  seem  to  be  good 
breeding  places  for  flies?     Can  you  think  of  any  ways  in  which  these 
conditions  might  be  avoided? 

11.  Why  is  it  that  barefooted  people  are  apt  to  contract  the  hook- 
worm disease?    Where  is  this  disease  most  common? 

12.  Describe  some  country  farmhouse  with  which  you  are  familiar 
where  conditions  of  perfect  cleanliness  exist  and  tell  what  measures 
have  been  taken  to  make  all  the  premises  thus  clean  and  sanitary. 

13.  Can  you  think  of  any  reason  why  health  officers  do  not  give 
attention  to  indigestion  while  they  do  to  measles  ? 

14.  Why  is  it  that  fewer  soldiers  in  our  armies  die  of  disease  than 
they  did  twenty-five  years  ago?    Why  cannot  a  city  be  just  as  well 
guarded  as  an  army  can? 


SECTION  II 
WHAT  THE  BODY  DOES  WITH  ITS  FOOD 

CHAPTER  I 
HOW  THE   BLOOD    CARRIES   THE   FOOD 

EVERY  minute  many  parts  of  our  bodies  are  working 
and  are  demanding  food.  The  digestive  organs  take  the 
food  we  eat  and  change  it  until  it  is  in  condition  to  nourish 
the  body ;  their  work  is  done  when  the  prepared  food  is 
taken  up  by  the  blood.  Then  it  remains  for  the  blood  to 
carry  the  liquid  food  where  it  is  needed,  to  all  parts  of  the 
body. 

What  the  Blood  Contains.  —  The  blood  contains  a 
great  deal  more  than  the  food  which  the  digestive  organs 
prepare  for  it.  About  one-thirteenth  of  a  person's  weight 
is  the  weight  of  his  blood  ;  a  person  weighing  100  pounds 
has  about  four  quarts  of  blood.  There  is  nothing  about  a 
drop  of  blood,  glistening  and  of  a  beautiful  red  color,  that 
would  suggest  the  marvels  it  contains.  It  is  more  than 
likely  that  science  does  not  yet  know  all  about  them, 
though  the  microscope  has  discovered  many  wonders. 
First,  the  liquid  part  of  blood,  called  plasma,  is  not  red ; 
it  is  almost  colorless.  Plasma  is  largely  made  up  of 
water ;  it  also  contains  the  digested  and  dissolved  food 
and  certain  other  substances  that  have  been  taken  from 

101 


102       .  PHYSIOLOGY   AND   HEALTH 

the  intestine.  Floating  in  it  are  millions  upon  millions 
of  tiny  little  bodies  called  corpuscles.  Most  of  them  are 
of  a  reddish  hue ;  their  presence  in  the  plasma  gives  the 
blood  its  red  color  (see  colored  illustration). 

Each  corpuscle  is  alive  and  at  work.  There  must  be  a 
great  deal  of  work  for  them  to  do,  because  when  we 
count  them,  we  find  more  than  5,000,000  in  a  drop  about 
the  size  of  a  large  pinhead.  The  number  of  corpuscles  at 
work  in  your  entire  body  is  greater  than  the  whole  number 
of  people  who  have  lived  in  the  world  from  the  earliest 
time  until  to-day.  Besides  the  red  corpuscles  there  are 
others  which  are  transparent  or  bluish  in  color. 

Red  Corpuscles.  —  The  red  corpuscles  are  so  small 
that  a  row  of  3200  would  be  only  an  inch  long.  The 
picture  facing  this  page  was  drawn  as  they  appeared 
to  the  artist  when  looking  at  a  tiny  speck  of  blood  under 
a  microscope.  They  seemed  to  him  like  round  discs, 
pinched  in  at  the  middle.  Those  who  have  had  opportu- 
nity to  watch  them  as  they  are  circulating  in  the  blood 
vessels  say  that  there  they  look  very  much  like  tiny, 
shallow  bowls.  They  are  a  pale  red  because  they  contain 
a  red  substance  (called  hemoglobin)  that  is  greedy  for 
oxygen,  and  always  seizes  as  much  of  it  as  it  can.  The  red 
corpuscles  are,  therefore,  the  oxygen  carriers  of  the  blood ; 
they  take  oxygen  to  every  part  of  the  body,  at  the  same 
time  that  the  blood  plasma  carries  food  to  every  part. 
Thus  the  blood  carries  all  over  the  body  the  two  things 
that  we  found  to  be  necessary  for  combustion  —  fuel-food 
and  oxygen.  The  red  corpuscles  never  go  out  into  the 
air  to  get  oxygen,  and  yet  every  minute  or  so  they  take 
on  a  fresh  supply  of  it.  The  means  by  which  oxygen  is 


5    0     •"• 

2;  I  < 


3  B"g  B 

w    ^^  *"**    tr* 

SL  6  c 


^    S-       hH 


c.   d 

t? 


HOW  THE  BLOOD   CARRIES  THE   FOOD  103 

brought  to  these  millions  upon  millions  of  tiny  workers 
will  be  explained  in  a  later  chapter. 

White  Corpuscles.  —  The  corpuscles  that  are  trans- 
parent and  slightly  bluish  are  called  white  corpuscles. 
There  is  one  white  corpuscle  to  about  700  red  ones ;  how 
many  white  ones,  then,  in  a  drop  the  size  of  a  pinhead? 
Although  the  white  corpuscles  are  slightly  larger  than  the 
red,  they  are  still  very  tiny.  They  are  somewhat  spherical 
in  shape,  as  shown  in  the  illustration  below.  Their  work 
is  very  different  from  that  of  the  red  corpuscles ;  it  requires 
them  to  change  their  shape  and  for  this  reason  the  micro- 
scope shows  them  with  a  variety  of  forms.  Like  the  Home 
Guard  in  an  army,  they  protect  our  bodies  from  invaders ; 
it  is  their  business  to  be  constantly  watchful  for  any 
irritating  substances  or  germ  enemies  that  may  find  an 
entrance  into  the  body,  and  to 
do  their  utmost  to  dispose  of  *^?:i? 

such  enemies  before  they  cause  fc;:>-^ff  ,£. 

trouble    or    disease.      Small   as  «^.  '' W     *T 

t  •  ••      .---/:.•<•"/ 

these    corpuscles  are,   they   are 

larger  than  most  of  the  disease  / 

germs ;    their  method  of    fight-  ' 

ing  is  to  try  to   capture   their  s-';5f'-- 

enemies.      They    dispose    of    a  FIG.  27. —  WHITE  BLOOD 

captured    enemy   by    eating    it  CORPUSCLES. 

(see  Figure  27);    i.e.  taking  it  ^^tV 

into  their  bodies  and  destroying  gulfing  and  destroying  bac- 

it.     Stories  are  told  about  the  teria-    The  black  spheres 

are  bacteria. 

manner  in  which  the  white  cor- 
puscles sacrifice  their  lives  for  the  protection  of  the  body, 
and  how  when  an  invader  comes  they  send  out  calls  to 


104  PHYSIOLOGY  AND   HEALTH 

each  other  for  help  at  some  particular  spot.  These  stories 
are  rather  fanciful ;  the  fact  seems  to  be  that  these  cor- 
puscles are  constantly  going  around  the  body,  and  when 
there  is  trouble  at  any  spot,  those  passing  that  way  stop 
to  see  what  the  matter  is  —  much  as  policemen  shoulder 
their  way  into  a  crowd  if  one  begins  to  collect.  In  case 
the  trouble  is  more  serious  than  the  passing  corpuscles 
can  handle,  more  blood  is  called  to  the  spot,  and  in  it 
come  more  white  corpuscles. 

Blood  Plates.  —  There  is  a  third  kind  of  corpuscles  in 
the  blood,  called  blood  plates.  They  appear  to  have  noth- 
ing to  do  until  the  blood  begins  to  flow  from  a  cut  or 
bruise ;  then  they  set  to  work  to  stop  the  loss  of  blood  by 
helping  to  form  a  clot. 

Discoveries  about  the  Blood.  —  It  has  always  been 
known  that  there  is  blood  in  all  parts  of  the  body,  be- 
cause wherever  the  body  is  cut  it  will  bleed.  But  it 
was  a  long  time  before  men  discovered  that  the  blood  is 
actually  pumped  by  the  heart  and  flows  around  the  body. 
It  is  difficult  to  realize  that  these  facts,  which  can  be  given 
in  so  few  words,  represent  the  results  of  the  investigations 
of  many  men  who  worked  all  their  lives  to  find  out  what 
is  now  to  us  a  commonplace.  Probably  no  explorer  who 
rejoiced  over  the  discovery  of  a  new  continent  or  a  new 
race  of  men,  was  ever  more  delighted  at  his  success  than 
were  the  two  scientists  who  made  the  greatest  discoveries 
about  the  blood. 

Discovery  of  Blood  Vessels.  -  -  The  first  one  was  a 
world-famous  Greek  physician,  named  Galen,  who 
practiced  medicine  in  Rome  in  the  second  half  of  the 
second  century.  He  watched  and  experimented  and 


HOW  THE  BLOOD   CARRIES  THE  FOOD  105 

became  convinced  that  there  are  two  kinds  of  blood : 
bright  red  blood  in  a  set  of  closed  tubes  called  arteries 
and  a  purplish  red  blood  in  another  set  of  closed  tubes 
called  veins. 

Discovery  of  the  Circulation.  —  For  fourteen  hundred 
years  his  theory  was  satisfactory  to  scientists;  they 
found  out  much  more  than  he  had  known  about  the 
arteries  and  veins,  but  it  was  not  until  the  seventeenth 
century  that  the  next  great  secret  was  discovered.  Then 
an  Englishman,  William  Harvey,  found  that  the  blood, 
instead  of  washing  about  like  water  in  a  pond,  travels 
in  a  definite  circuit,  with  the  greatest  regularity  and 
precision,  and  is  pumped  along  that  circuit  by  the  heart. 
When  he  announced  this  discovery  Harvey  was  laughed 
at  and  abused ;  but  he  was  right,  and  his  name  is  every- 
where associated  with  the  great  new  fact,  which  he  called 
the  "  circulation  of  the  blood."  How  the  blood  passed 
from  the  arteries  to  the  veins,  Harvey  did  not  know,  for 
the  tiny  connecting  blood  vessels  are  so  small  that  he 
never  saw  them. 

An  Outline  of  the  Circulation.  —  It  is  not  easy  to 
describe  the  circulation  of  the  blood,  because  the  process, 
while  perfectly  simple  in  principle,  becomes  complex 
when  represented.  A  brief  outline  of  it  may  be  of  help 
at  the  beginning. 

The  heart  pumps  the  pure  blood  into  the  set  of  tubes 
called  arteries.  These  divide  into  smaller  and  smaller 
branches,  like  the  branches  of  a  tree,  and  one  or  more  of 
the  tiny  branches  goes  to  every  part  of  the  body;  we 
might  call  those  twigs.  The  ends  of  the  smallest  twigs 
again  divide  into  very  many  still  smaller  ones,  called 


106  PHYSIOLOGY   AND   HEALTH 

capillaries ;  these  are  altogether  too  small  to  be  seen  with- 
out a  microscope.  While  the  blood  is  flowing  through 
the  capillaries,  it  loses  its  bright  red  color.  After  passing 
through  them  it  enters  the  set  of  tubes  called  veins,  and 
in  them  is  carried  back  to  the  heart.  From  the  heart  it 
is  pumped  to  the  lungs,  where,  by  a  process  that  will  be 
described  later,  it  is  made  bright  and  pure,  after  which 
it  flows  back  to  the  heart  —  ready  to  start  again  on  the 
route  around  the  body. 

The  Network  of  Blood  Vessels.  —  The  blood  goes  on 
a  distinct  track,  i.e.  it  goes  only  where  the  blood  vessels 
go.  But  they  go  everywhere,  for  every  single  part,  even 
a  section  as  small  as  a  pea,  contains  arteries,  capillaries, 
and  veins,  forming  side  routes  that  branch  off  from  the 
main  lines.  All  the  blood  in  the  body  goes  through  the 
heart  hundreds  of  times  a  day.  Not  all  the  blood  that 
leaves  the  heart  at  one  time  goes  over  the  same  route  — 
just  as  all  the  passengers  that  leave  a  great  railroad 
terminal  do  not  go  on  the  same  lines  or  to  the  same 
destination.  Some  of  them  may  go  only  a  few  miles, 
others  to  the  furthest  point  on  the  longest  line.  Part 
of  the  blood  that  leaves  the  heart  may  travel  in  the  arteries 
for  only  a  few  inches,  then  go  into  some  capillaries,  then 
into  the  veins,  and  then,  in  a  very  short  time,  back  to  the 
heart  again  —  before  the  rest  of  the  blood  that  started 
with  it  has  had  time  to  go  through  the  longer  arteries. 
These  differences  in  route  and  speed  need  not  confuse 
us  at  all ;  they  will  only  add  to  the  interest  of  the 
picture  if  the  following  outline  of  what  happens  is 
kept  clearly  in  mind.  Whatever  route  be  taken, 
whether  to  the  extremities  of  the  body,  or  to  some 


HOW  THE  BLOOD   CARRIES  THE   FOOD  107 

muscle  very  near  the  heart,  the  course  of  the  blood  is 
always: 

1.  heart  to  arteries 

2.  arteries  to  capillaries 

3.  capillaries  to  veins 

4.  veins  to  heart 

5.  heart  to  lungs 

6.  lungs  to  heart 

QUESTIONS 

1.  What  gives  the  blood  its  red  color? 

2.  What  do  the  red  corpuscles  do  for  us?    The  white  corpuscles? 

3.  What  part  of  the  blood  carries  the  digested  food  over  the  body? 

4.  Why  does  a  cut  always  bleed? 

5.  What  provision  is  made  by  our  bodies  for  stopping  bleeding? 

6.  Will  a  pin  prick  (provided  it  is  deep  enough)  draw  blood  wher- 
ever it  pierces  the  skin?     If  so,  what  does  this  show  about  the  blood 
vessels  ? 

7.  To  what  two  men  do  we  owe  much  of  our  knowledge  of  the  way 
in  which  the  blood  flows  through  our  bodies  ? 

8.  What  three  sets  of  tubes  are  used  to  carry  the  blood?    What 
are  the  capillaries? 

9.  Describe  the  journey  that  the  blood  takes  on  its  circuit  from  the 
heart  and  back  again. 

10.  Does  all  the  blood  that  the  heart  pumps  out  at  one  time  travel 
the  same  distance? 

11.  What  would  be  the  longest  distance  that  a  drop  of  blood  could 
travel  in  the  body? 

To  THE  TEACHER.    If  possible,  have  pupils  examine  a  drop  of  blood 
under  the  microscope. 


CHAPTER   II 
THE   HEART   AND   THE   CIRCULATION 

The  Heart  as  a  Pump.  —  It  is  easy  to  find  the  spot  at 
which  the  heart  beats ;  that  spot  is  where  the  apex  or 
lower  point  of  it  comes.  If  you  put  the  little  finger  of 
your  right  hand  over  that  spot  and  your  thumb  in  the 
hollow  in  front  of  your  neck,  the  heart  will  lie  under  your 


Au. 


Au. 


Valve 


-Yen. 


FIG.  28.  —  THE  VALVES  OF  THE  HEART. 

The  right  side  of  the  heart  shown  diagrammatically.  A  represents  the  time 
when  the  blood  is  flowing  into  the  auricle  and  the  ventricle  from  the  veins,  and 
B  the  stage  when  the  ventricle  is  contracting  to  force  the  blood  into  the  pul- 
monary arteries.  Aw.,  auricle;  Fen.,  ventricle. 

hand.     It  is  about  the  size  of  your  fist,  but  pear-shaped, 
with  the  upper  and  larger  end  lying  in  the  middle  of  the 

108 


THE   HEART  AND  THE   CIRCULATION  109 

chest  and  the  lower  end  turned  to  the  left,  where  you  feel 
it  thump. 

The  heart  is  a  muscle,  or  rather  a  group  of  muscles  so 
arranged  that  they  work  like  a  pump.  In  fact,  the  heart 
is  a  double  pump,  for  there  is  a  partition  running  up  and 
down,  which  really  divides  the  heart  into  two  hearts ; 
they  are  attached  to  each  other,  but  so  separated  that  no 
drop  of  blood  can  flow  from  one  side  to  the  other.  On  one 
side  is  the  pure  blood  which  is  to  go  out  into  the  body; 
on  the  other  side  is  the  impure  blood  which  is  to  go  to 
the  lungs.  Each  side  of  the  heart  has  two  cavities,  as 
shown  in  Figure  28.  Those  on  the  right  side  are  called 
the  right  auricle  and  the  right  ventricle,  those  on  the 
left,  the  left  auricle  and  the  left  ventricle.  The  muscles 
of  the  left  ventricle  are  much  stronger  than  those  of  the 
right  because  it  has  to  pump  harder. 

The  Heart  Beat.  —  As  long  as  a  person  lives,  whether 
he  is  awake  or  asleep,  his  heart  continues  to  pump  blood 
through  the  blood  vessels ;  the  motion  of  the  blood  and 
the  work  of  the  heart  never  cease.  In  order  to  pump 
continuously,  the  heart  evidently  must  be  adjusted  so 
that  it  can  work  with  the  least  possible  amount  of  effort. 
It  is  not  surprising,  therefore,  to  find  that  the  heart  takes 
a  little  rest  after  every  beat,  really  resting  longer  than  it 
works. 

What  we  call  the  "  heart  beat  "  means  simply  the  con- 
traction of  the  muscles;  this  contraction  squeezes  the 
blood  out  into  the  blood  vessels.  Little  gates,  or  valves, 
opening  only  one  way,  determine  the  direction  of  the 
blood  flow.  A  study  of  Figure  28  will  easily  show  why, 
when  the  heart  beats,  the  blood  is  forced  in  the  direction 


110  .       PHYSIOLOGY   AND   HEALTH 

of  the  arrows  and  how  it  is  prevented  from  flowing  back- 
ward. As  soon  as  the  heart  relaxes  from  its  contraction, 
blood  flows  into  it  again  from  the  veins.  A  grown  person's 
heart  beats  from  70  to  80  times  a  minute,  a  child's  heart 
beats  faster,  and  a  baby's  as  fast  as  120  times  a  minute. 
The  heart  beat  is  firm  and  strong  when  one  is  in  good 
health ;  when  one  is  ill  it  becomes  weak. 

The  Pulse  Beat.  —  Each  time  the  heart  beats,  and  so 
forces  the  blood  into  the  arteries,  the  pressure  produced 
is  felt  through  the  arteries  and  causes  them  to  swell 
slightly  as  the  blood  passes.  The  artery  at  the  wrist  is 
so  near  the  surface  that  we  can  feel  the  swelling  there. 
This  we  call  the  pulse.  There  is  a  pulse  in  all  the  arteries, 
but  the  throbbing  cannot  readily  be  felt  in  most  of  them  as 
they  are  deep  in  the  muscle.  The  wrist  is  the  best  place 
for  testing  the  pulse  beat,  but  it  can  be  felt  at  the  neck, 
just  under  the  lower  jaw,  and  also  at  the  temples.  Physi- 
cians feel  the  pulse  of  a  sick  person,  for  this  tells  them  a 
great  deal  about  the  general  condition  of  the  patient. 

When  the  heart  beats,  both  sides  act  at  the  same  time, 
each  doing  its  separate  work.  Let  us  trace  what  happens, 
from  the  time  of  one  heart  beat  up  to  the  time  when  the 
heart  is  ready  to  beat  again. 

Work  of  the  Left  Side  of  the  Heart.  —  Before  the 
beat  comes,  the  left  auricle,  which  is  really  a  reservoir, 
contains  bright  red  blood ;  it  contracts  and  sends  this 
blood  into  the  left  ventricle ;  then  the  ventricle  contracts 
and  forces  out  all  the  blood  that  is  in  it. 

Blood  in  the  Arteries.  —  The  blood  passes  into  a  large 
artery  which  is  shown  in  red  in  the  colored  illustration 
opposite.  This  artery  gives  off  some  large  branches  (to 


THE   HEART  AND   THE   CIRCULATION 


111 


Vein 


the  head  and  arms)  and  then  runs  down  the  body,  giving 
off  branches  all  the  way.  The  branching  arteries  also  give 
off  smaller  branches  until  finally  they  become  thousands 
of  minute  tubes  which  enter  every  organ  of  the  body. 
This  does  not  mean  that  all  the  large  arteries  are  in  the 
upper  part  of  the  body,  and  all  the  small  ones  in  the  legs ; 
there  are  tiny  artery  branches  in  the  chest,  near  the  heart, 
as  well  as  in  the  extremities. 

Blood  in  the  Capillaries.  —  The  blood  goes  through 
these  artery  branches  until  finally  they  end  in  even  smaller 
tubes,  the  capillaries,  like  those 
shown  in  Figure  29.  These  are 
too  small  to  be  seen  except 
with  the  aid  of  a  microscope ; 
some  of  them  are  so  small  that 
the  corpuscles,  tiny  as  they  are, 
have  to  go  through  in  single  file. 
It  is  while  the  blood  is  in  these 
capillaries  that  it  gives  up  to 
the  living  parts  of  the  body  the 
food  materials  which  it  holds. 
Every  part  of  the  body  is  filled 
with  capillaries,  and  every  part 
gets  its  share  of  the  food  which 
passes  out  through  their  deli- 
cate walls.  Here  again,  we  see 
the  smallest  parts  doing  the 
most  important  work;  the 

heart  is  a  giant  compared  with  the  capillaries,  but 
its  work  is  performed  chiefly  to  supply  them  with 
food. 


Capillaries 
FIG.  29.  —  CAPILLARIES. 

Showing  the  end  of  an  artery, 
capillaries,  and  a  vein  arising 
from  the  capillaries. 


112  PHYSIOLOGY   AND   HEALTH 

Blood  in  the  Veins.  —  After  its  journey  through  the 
capillaries,  where  it  not  only  leaves  the  food  but  also  takes 
up  waste  matter,  the  blood  is  ready  to  go  back  to  the 
heart.  It  needs  to  be  purified  before  it  can  be  of  further 
use  to  the  body.  So  the  little  capillary  branches  combine 
to  form  the  larger  blood  vessels  called  veins ;  and  the 
veins  keep  combining  (just  the  opposite  of  the  arteries, 
which  kept  branching),  until  finally  they  unite  in  two 
large  veins,  which  pour  the  blood  into  the  right  auricle 
of  the  heart. 

Work  of  the  Right  Side  of  the  Heart.  —  At  the  same 
time  that  the  left  ventricle  contracted,  the  other  ventricle, 
the  right  one,  was  also  making  its  contraction.  The  right 
ventricle  sends  the  blood  to  the  lungs  to  be  purified; 
this  is  a  much  shorter  trip  than  the  journey  around  the 
body.  At  every  heart  beat  both  ventricles  contract ; 
the  left  one  sending  pure  blood  out  to  the  body,  and  the 
right  sending  impure  blood  to  the  lungs  to  be  purified. 
From  the  lungs  the  purified  blood  goes  to  the  left  side  of 
the  heart,  ready  to  be  sent  out  again  to  the  body. 

The  path  of  the  blood  is  always  this  :  out  from  the  left 
side  of  the  heart  to  feed  the  body  and  gather  up  wastes ; 
then  to  the  right  side  of  the  heart,  to  be  sent  to  the  lungs 
for  purifying ;  then  back  again  to  the  left  side  to  go  out 
again  to  the  body.  A  grown  man  has  about  six  quarts 
of  blood ;  at  each  beat  of  the  heart  about  half  a  cup  full 
of  blood  is  sent  out  to  the  body  from  the  left  side  of  the 
heart  and  half  a  cup  full  is  sent  to  the  lungs  from  the  right 
side. 

Relation  of  Arteries  and  Veins. --The  arteries  lead 
away  from  the  heart,  and  all  of  them,  except  those  that 


THE   HEART   AND   THE   CIRCULATION  113 

go  from  the  heart  to  the  lungs,  carry  pure  blood.  The 
veins  lead  to  and  enter  the  heart ;  all  of  them  carry  im- 
pure blood,  except  those  that  go  from  the  lungs  to  the 
heart.  The  arteries  are  embedded  deep  in  the  muscles; 
the  veins  are  nearer  the  surface.  A  cut  in  the  flesh  is 
almost  sure  to  cause  bleeding  from  the  veins,  but  it  takes 
a  very  deep  cut  to  injure  the  arteries.  If  you  will  let 
your  hand  hang  down  for  a  minute,  you  can  see  the 
position  of  the  veins  by  the  blue  lines  that  will  appear  on 
the  back  of  the  hand.  If  you  wind  a  rubber  band 
tightly  around  one  of  your  fingers,  the  finger  will  soon 
become  dark  colored,  being  gorged  with  blood.  From  the 
facts  given  above  can  you  explain  why  the  finger  becomes 
a  dark  red  instead  of  a  bright  red  ? 

The  Feeders  of  the  Body.  -  -  The  capillaries  are  the 
smallest  and  the  most  important  of  the  blood  vessels. 
The  chief  purpose  of  the  heart,  the  arteries,  and  the  veins 
is  to  keep  a  supply  of  good  pure  food  and  oxygen  going 
to  the  capillaries,  so  that  they  may  feed  the  body. 
Remember  that  they  are  not  away  off  at  the  end  of  some 
long  line  of  arteries,  but  that  they  are  everywhere,  in 
all  parts  of  the  body ;  if  there  were  any  part  that  had  no 
capillaries,  it  would  starve  and  die. 

Lymph,  in  and  around  the  Capillaries.  —  As  the  blood 
goes  through  the  capillaries,  the  red  corpuscles  give  up  their 
oxygen.  The  oxygen  passes  out  through  the  thin  walls  of 
the  capillaries ;  but  the  red  corpuscles  themselves  never 
leave  the  blood  vessels,  except  in  case  of  accident.  Some 
of  the  liquid  part  of  the  blood,  however,  does  ooze  through 
the  capillary  walls  into  the  spaces  around  them.  This 
clear  and  watery  liquid  is  really  the  blood  plasma, 


114 


PHYSIOLOGY   AND   HEALTH 


which  is  then  called  lymph.  The  lymph  actually  bathes 
the  living  parts  of  the  body;  and  as  it  contains  the 
dissolved  food  that  was  in  the  blood,  it  can  give  this  food 
directly  to  the  parts  of  the  body  that 
need  it. 

At  the  same  time,  the  lymph  receives 
from  the  living  tissues  the  waste  materials 
they  have  produced  as  they  worked. 
These  must  be  carried  away  or  the  tissues 
cannot  go  on  working.  The  flow  of  the 
lymph  is  not  nearly  so  rapid  as  that  of  the 
blood,  but  slowly  it  moves  away  from  the 
living  tissues  carrying  the  wastes  it  has 
taken  up,  its  place  being  taken  by  fresh 
lymph  from  the  capillaries.  Gradually 
the  lymph  collects  in  tiny  tubes,  called 
•  lymph  vessels,  and  these  unite  finally  in 
two  large  vessels  that  empty  into  the 
veins  in  the  neck.  Thus  in  the  end,  the 
lymph  again  becomes  a  part  of  the  blood 
plasma  in  the  blood  vessels.  Little  organs 
called  lymph  glands  are  found  along  some . 
of  the  lymph  vessels ;  they  may  perhaps 
help  to  filter  out  some  of  the  wastes. 
Because  it  carries  away  the  wastes,  the 
lymph  system  has  sometimes  been  called 
FIG.  so.  — LYMPH  the  drainage  system.  This  name,  how- 
ever, describes  only  half  its  work,  for  it 
is  as  much  the  mission  of  the  lymph  to 
carry  food  to  the  living  parts  of  the  body  as  to  carry  off 
the  wastes. 


VESSELS  IN  THE 
ARM. 


THE   HEART  AND   THE  CIRCULATION  115 

QUESTIONS 

1.  Describe  what  you  would  see  if  you  could  cut  the  heart  in  two 
lengthwise  and  look  into  it. 

2.  Suppose  a  drop  of  blood  is  entering  the  left  auricle.     Describe 
the  journey  that  it  takes  before  it  reaches  the  left  auricle  again. 

3.  What  do  you  think  would  happen  if  the  heart  valves  did  not 
work? 

4.  With  your  left  hand  grasp  your  right  wrist,  pressing  the  thumb 
firmly  against  the  lower  end  of  the  radius  or  bone  on  the  thumb  side 
of  the  arm.     Count  the  number  of  beats  that  you  feel  in  a  minute. 

5.  What  is  this  throbbing  movement  called,  and  why  can  it  be 
felt  so  plainly  at  the  wrist?    Where  else  can  it  be  felt? 

6.  What  can  you  tell  about  the  heart  from  feeling  the  pulse? 

7.  What  is  the  work  of  the  capillaries  ?    Why  are  these  tiny  vessels 
so  important? 

8.  In  what  respects  is  the  blood  in  the  veins  different  from  the 
blood  carried  by  the  arteries? 

9.  Why  is  it  that  when  you  cut  your  finger  the  blood  that  flows 
from 'it  is  likely  to  be  a  very  dark  red? 

10.  What  is  lymph?  Where  does  it  come  from  and  where  does  it 
go?  What  two  duties  does  it  perform? 

To  THE  TEACHER.  Borrow  a  stethoscope  from  some  physician  if 
you  can  and  have  pupils  determine  with  it  the  location  of  the  heart 
and  the  strength  of  its  beat. 


CHAPTER   III 
THE   CONTROL   OF   THE  BLOOD   FLOW 

Differences  in  the  Heart  Beat.  -  -  The  body  is  able  to 
regulate,  not  only  the  rate  at  which  the  heart  shall  pump 
the  blood,  but  also  the  size  of  the  blood  vessels  and  so 
the  amount  of  blood  carried  in  them.  Usually  all  this 
occurs  without  our  being  in  the  least  aware  of  what  is 
happening,  nor  could  we,  however  hard  we  tried,  make 
the  heart  beat  slower  or  faster.  A  simple  test  will  show 
decided  differences  in  the  heart  beat.  (1)  Count  your 
pulse  after  you  have  been  sitting  still  studying  for  half 
an  hour ;  write  down  the  rate.  (2)  Go  out  and  •  run 
around  briskly  for  five  minutes;  then  count  the  pulse 
and  record  the  rate.  (3)  Go  in  and  sit  still  for  twenty 
minutes ;  again  record  the  rate.  (4)  Stand  still,  and  see 
whether  you  can  make  your  pulse  go  ten  beats  faster  by 
thinking  about  increasing  it.  Three  of  your  records  will 
doubtless  be  somewhat  like  these : 

When  sitting,  about  85  beats  per  minute. 

After  running,  about  115  beats  per  minute. 

After  sitting  still  twenty  minutes,  about  90  beats  per 
minute. 

Did  you  find  that  you  could  increase  the  rate  of  your 
heart  beat  by  thinking  about  it?  No,  and  yet  it  was 
increased  when  you  were  running;  how  this  is  done 
can  be  more  satisfactorily  explained  later. 

116 


THE   CONTROL  OF  THE  BLOOD   FLOW  117 

How  Each  Organ  Gets  Its  Blood  Supply.  —  Not  only 
will  the  heart  beat  faster  if  the  whole  body  needs  more 
blood  to  use,  but  each  separate  part  of  the  body  is  fur- 
nished with  a  larger  or  smaller  supply  as  needed.  This 
may  be  seen  from  a  few  simple  tests.  (1)  Bare  the  arm, 
rub  it  briskly,  and  notice  how  red  it  turns.  That  is 
because  more  blood  is  flowing  through  it  than  usual. 
(2)  Place  the  arm  in  hot  water  and  it  will  become  red  in 
the  same  way  for  the  same  reason.  (3)  Put  the  arm  in 
cold  water  and  it  will  turn  white,  since  less  blood  flows 
through  it  than  usual.  (4)  When  a  person  blushes,  it  is 
because  more  blood  than  usual  is  allowed  to  go  through 
the  skin  of  the  cheeks ;  when  one  turns  pale,  less  blood 
than  usual  is  sent  through. 

The  fact  is  that  the  brain,  which  is  a  wonderful  organ, 
has  the  power  to  send  the  blood  to  any  part  that  needs 
it.  When  an  organ  begins  to  work  vigorously,  it  gets  an 
extra  blood  supply ;  and,  in  consequence,  the  other  organs 
cannot  get  quite  -as  much  as  usual.  If  the  brain  begins 
to  work  hard,  it  receives  more  blood,  and  the  arm,  which 
then  receives  less,  actually  shrinks  a  little  in  size,  as  can 
be  proved  by  delicate  tests.  When  the  brain  goes  to  sleep 
it  shrinks  a  bit,  as  it  needs  and  receives  less  blood. 

Changes  in  Blood  Supply.  —  One  very  interesting  case 
is  that  of  a  man  who,  by  an  accident,  had  a  bit  of  the 
skull  removed  in  such  a  manner  that  his  brain  could  be 
seen  and  watched.  It  was  found  by  testing  him  that  the 
amount  of  blood  going  to  his  brain  increased  and  de- 
creased regularly  according  to  the  work  his  brain  was  doing. 
When  he  was  asleep  it  received  very  little,  but  the  moment 
he  waked  a  greater  supply  was  turned  into  the  brain. 


118  PHYSIOLOGY   AND   HEALTH 

In  the  same  way,  every  organ  gets  an  extra  supply  of 
blood  when  it  begins  to  work,  and  it  cannot  do  its  best 
till  it  gets  its  full  supply.  If  the  foot,  the  arm,  the  legs, 
or  the  stomach  are  to  do  hard  work,  the  first  thing  that 
must  happen  is  for  the  brain  to  send  them  an  extra  blood 
supply.  It  is  evident,  therefore,  why  an  athlete  finds  it 
helpful  to  run  about,  to  "  warm  up  "  as  he  calls  it,  before 
the  race  begins ;  this  "  warming  up  "  starts  the  blood 
flowing  through  the  muscles  he  is  going  to  use,  so  that 
when  the  race  is  called  his  muscles  are  ready  to  work 
hard.  Every  change  in  occupation  changes  the  dis- 
tribution of  the  blood  in  the  body,  so  that  the  parts  to 
be  used  get  more  blood  and  the  other  parts  less.  This 
change  is  made  by  means  of  the  tiny  muscles  in  the  blood 
vessels,  which  cause  them  to  become  larger  or  smaller. 
Of  course  this  is  done  without  our  attention  or  knowl- 
edge, even  though  it  is  controlled  by  the  brain. 

Through  its  ability  to  regulate,  quickly  and  accurately, 
the  amount  of  blood  sent  to  different  parts  of  the  body, 
the  brain  also  regulates  the  temperature  of  the  body. 

A  Good  Circulation.  —  It  will  not  do  much  good  to 
have  pure  blood  unless  it  is  kept  circulating  rapidly,  and 
so  the  heart  must  be  kept  strong.  Like  any  other  muscle 
the  heart  grows  stronger  by  use.  Of  course  it  is  really 
beating  all  the  time,  and  so  is  always  being  used  to  some 
extent.  But  vigorous  exercise,  like  running,  makes  it 
beat  faster  and  stronger,  and  it  is  strengthened  by  the 
extra  work.  On  the  other  hand,  a  quiet  life,  a  "sedentary 
life  "  as  it  is  called,  weakens  the  heart  because  it  does  not 
have  enough  to  do.  Exercise  is  the  best  "  stimulant " 
for  a  healthy  heart ;  drugs  that  act  on  the  heart  really 


THE   CONTROL  OF  THE  BLOOD  FLOW  119 

weaken  it,  though  some  of  them  may  make  it  beat  a 
little  faster  for  a  short  time. 

The  Need  for  a  Good  Heart. '- —  If  a  boy  wants  to  stop  a 
runaway  horse,  he  may  think  that  what  he  needs  most  is 
good  leg  muscles  with  which  to  run  and  a  clear  head  to 
decide  what  to  do.  But  his  ability  to  run  depends  more 
upon  his  heart  than  upon  his  legs.  An  athlete  knows  that 
his  winning  depends  more  upon  his  heart  than  upon  his 
arms  or  legs.  When  any  special  need  comes,  the  muscles 
will  work  sufficiently  well  if  the  heart  is  strong  enough  to 
send  the  blood  through  the  body  rapidly  enough  to  carry 
away  all  the  poisons  that  accumulate  as  the  muscles 
work.  There  are  many  emergencies  in  life  which  require 
some  sudden  exertion;  the  heart  that  has  been  exer- 
cised every  day  by  doing  extra  work  is  ready  for  these 
emergencies. 

Sensible  Training  of  the  Heart.  —  Work  is  good  for 
the  heart,  but  it  is  not  wise  to  work  it  until  it  is  overtired. 
Long-continued  and  severe  exercise  is  apt  to  strain  and 
weaken  it.  Very  long  runs  or  long-continued  use  of  a 
jumping  rope  will  weaken  the  heart  instead  of  strengthen- 
ing it.  Sometimes  the  heart  is  so  overworked  as  to 
weaken  it  for  life.  One  athlete  tried  to  strengthen  his 
heart  by  running  up-stairs  repeatedly;  instead,  he  so 
overstrained  it  that  it  failed  him  when  the  contest  for 
which  he  was  preparing  came,  and  he  found  himself 
permanently  weakened  by  the  injudicious  exercise  he  had 
taken.  Growing  boys  and  girls  need  to  be  particularly 
careful  in  this  respect,  for  their  hearts  are  not  ready  for 
long-continued  exercise.  A  six-mile  walk  is  better  than 
a  twenty-five-mile  walk.  Plenty  of  light,  active  exercise, 


120  PHYSIOLOGY   AND   HEALTH 

not  taken  for  too  long  a  time,  is  the  best  means  of  building 
a  strong  heart. 

Drugs  to  Be  Avoided.  —  Tobacco  and  alcohol  are 
two  drugs  that  act  directly  upon  the  heart  in  such  a  way 
as  to  weaken  it.  That  explains  why  the  boy  who  smokes 
cigarettes,  and  thus  acquires  a  "  cigarette  heart,"  can 
never  in  all  his  life  be  as  strong  and  as  vigorous  as  he 
would  otherwise  be ;  his  heart  is  permanently  weakened. 
Every  one  knows  that  the  boys  who  are  training  for  athletic 
contests  are  forbidden  to  smoke ;  and  even  on  university 
teams,  made  up  of  grown  men,  no  trainer  would  allow 
the  use  of  tobacco  or  alcohol ;  he  wants  to  have  his  men 
"fit  to  win."  Many  occupations  that  require  active 
muscular  work  and  real  endurance  are  closed  to  a  man 
with  a  weak  heart;  he  is  restricted  to  " light  work." 
What  boy  wants  to  be  in  that  condition?  Life  insurance 
compaliies  will  not  issue  a  policy  to  one  whose  chances  of 
a  long  life  are  so  poor. 

Fainting.  —  The  ease  with  which  the  blood  distribution 
is  changed  has  some  unpleasant  results  and  one  of  them  is 
fainting.  When  a  person  faints  it  usually  means  that 
the  brain  is  not  getting  blood  enough,  thus  causing  uncon- 
sciousness. The  remedy  is  to  get  the  needed  blood  into 
the  brain  again.  Placing  the  head  a  little  lower  than  the 
body  helps  to  bring  this  about,  for  then  the  blood  tends 
to  run  into  the  brain  from  its  own  weight.  Usually 
lowering  the  head  is  all  that  is  needed,  and  as  soon  as  the 
necessary  amount  of  blood  has  reached  the  head  the 
person  recovers  consciousness ;  sometimes  it  is  best  to 
stimulate  the  action  of  the  heart,  which  can  usually  be 
done  by  dashing  a  little  cold  water  upon  the  face. 


THE   CONTROL  OF  THE  BLOOD  FLOW  121 

When  anybody  faints,  one  natural  impulse  is  to  lift 
the  person's  head,  which  as  a  rule  hinders  recovery.  An- 
other impulse  is  to  crowd  around  the  fainting  person, 
thus  shutting  off  the  fresh  air  that  such  a  person  particu- 
larly needs.  The  blood  will  not  fail  to  go  to  the  brain  in 
sufficient  quantity  unless  seriously  impeded ;  the  trouble 
may  be  due  to  improper  eating,  lack  of  exercise,  or  wearing 
around  the  waist  a  corset  or  a  belt  that  is  too  tight. 

Some  people  faint  more  easily  than  others, « but  the 
habit  may  usually  be  overcome  if  proper  attention  is 
given  to  the  ordinary  rules  of  health.  Some  become 
frightened  when  they  feel  faint.  The  sensible  thing  is  to 
regard  faintness  as  a  signal  from  the  brain  that  it  needs 
more  blood,  and  to  proceed  at  once  to  help  it  get  more. 
To  fall  over  in  a  dead  faint  is  frequently  sheer  heedlessness 
and  quite  unnecessary.  One  who  begins  to  feel  very  faint 
should  either  lie  down  for  five  minutes,  if  that  is  possible, 
or  else  sit  down  and  rest  the  head  on  the  knees  —  both 
positions  help  the  blood  to  flow  into  the  brain.  A  resolute 
determination  not  to.  faint  is  also  a  decided  help  in  all 
simple  fainting  attacks  ;  occasionally,  fainting  is  the  first 
symptom  of  a  serious  illness,  and  then  it  cannot  be  so 
readily  controlled. 

Bleeding.  -  -  The  heart  sends  the  blood  into  the  main 
artery  in  spurts,  pumping  it  with  force.  The  arteries, 
being  elastic  like  rubber,  stretch  a  little  as  the  blood 
flows  into  them,  and  the  result  is  that  a  short  distance 
away  from  the  heart  the  blood  begins  to  flow  more 
smoothly ;  and,  by  the  time  it  has  passed  through  the 
capillaries  and  is  on  its  way  through  the  veins,  the  spurt- 
ing has  ceased  entirely. 


122  PHYSIOLOGY  AND   HEALTH 

If  an  artery  is  cut,  the  blood  flows  out  very  rapidly  in 
strong  jets  ;  the  bleeding  must  be  stopped  quickly,  or  the 
person  will  bleed  to  death.  If  a  vein  is  cut,  the  bleeding 
is  not  so  rapid  and  consequently  is  not  so  dangerous.  But 
in  any  case  it  must  be  stopped,  for  even  through  a  wound 
in  a  vein  enough  blood  to  cause  death  might  be  lost  if 
the  flow  were  not  checked.  To  lose  a  few  teaspoonfuls 
of  blood  is  not  serious ;  it  may  make  one  faint  for  a  few 
moments,  but  that  feeling  will  quickly  pass.  Every  one 
ought  to  know  how  to  tell  whether  the  bleeding  is  slight 
and  will  take  care  of  itself,  or  whether  it  is  serious  and 
needs  instant  attention  if  the  life  of  the  bleeding  person 
is  to  be  saved. 

How  Bleeding  Is  Stopped.  —  In  most  accidents  that 
cause  bleeding  only  small  veins  or  capillaries  are  cut,  and 
the  result  is  not  serious.  Nature  has  made  provision  for 
taking  care  of  such  cases,  for  as  soon  as  a  blood  vessel 
is  broken  or  injured  the  blood  starts  to  work  to  close  the 
wound.  If  it  is  a  small  one,  it  will  soon  be  more  or  less 
completely  stopped  with  a  plug  of  blood  called  a  clot. 
It  is  believed  that  the  blood  plates  are  concerned  in  causing 
the  blood  to  clot.  This  process  can  be  helped  by  bringing 
the  edges  of  the  wound  together  and  binding  them  tightly 
with  a  strip  of  clean  cloth,  or  a  piece  of  surgeons'  plaster, 
until  the  bleeding  stops.  If  there  is  much  bleeding,  the 
plaster  will  not  stay  on,  and  in  that  case  the  cloth  is 
better.  For  a  time  the  blood  may  ooze  through  the 
cloth,  but  even  deep  wounds  in  the  veins  will  usually 
stop  bleeding  if  the  wounded  part  is  kept  quiet  and 
the  cloth  (called  a  ligature  when  so  used)  is  drawn  as 
tightly  as  possible.  The  tight  ligature  will  close  the 


THE   CONTROL  OF  THE  BLOOD   FLOW 


123 


•Artery 


broken  blood  vessel  and  help  keep  the  blood 
still  until  it  can  clot. 

We  can  see  what  the  clot  is  like  by  ob- 
serving some  blood  drawn  into  a  small  dish. 
If  it  is  allowed  to  stand  for  a  few  minutes, 
it  stiffens,  and  finally  the  blood  is  changed 
into  a  firm  jelly  that  will  turn  out  of  the 
dish  as  one  mass ;  in  other  words,  the  blood 
has  clotted.  The  blood  will  not  remain  liq- 
uid after  it  has  been  drawn 
from  the  blood  vessels.  Keep- 
ing it  warm  will  not  prevent 
its  clotting ;  nor  will  warming 
it  make  it  liquid  again  after  FlG 
it  has  clotted. 

Bleeding  from  Arteries.  - 
The  arteries  lie  so  deep  that  they  are  not 
often  injured,  but  when  they  are  cut  the 
case  is  serious ;  a  person's  life  may  depend 
upon  the  promptness  and  efficiency  of  some 
chance  bystander.  If  the  blood  comes  in 
spurts  from  a  cut  or  wound  of  any  sort,  an 
artery  has  been  injured.  There  is  no  hope 
that  the  clot  can  be  formed  quickly  enough 
to  stop  the  flow  from  an  artery. 

The  only  way  to  stop  the  bleeding  is  to 
check  the  flow  of  the  blood  into  the  broken 
part  of  the  artery;  this  is  done  by  com- 
pressing the  artery  above  the  cut,  that  is, 
between  the  heart  which  is  pumping  the 
blood  into  the  artery,  and  the  cut  where  it 


31.— AR- 
TERIES IN  THE 
ARM. 


FIG.  32.  — AR- 
TERIES IN  THE 
LEG. 


This  artery  is  in 
the  front  of 
the  leg  above 
the  knee,  but 
behind  it  be- 
low the  knee. 


124 


PHYSIOLOGY  AND   HEALTH 


FIG.  33.  —  SHOWING 
THE  METHOD  OF 
GRASPING  THE  ARM 
TO  STOP  BLEEDING 
FROM  AN  ARTERY. 


is  running  out.  The  arteries  in  the  arms 
and  the  legs  are  more  liable  to  injury 
than  others,  and  the  treatment  in  such 
cases  is  simple.  Figures  31  and  32  show 
the  course  of  the  chief  arteries  in  the 
arm  and  the  leg.  Figure  33  shows  a 
simple  method  of  grasping  the  arm  so 
as  to  compress  the  artery ;  this  will  tem- 
porarily stop  arterial  bleeding  in  the 
arm  anywhere  below  the  elbow. 

While  one  person  is  compressing  the 
artery,  another  should  make  a  ligature 
(or  tourniquet)  and  put  it  around  the 
arm  above  the  cut,  placing  a  stick  as  in- 
dicated in  Figure  34.  The  stick  should 

then  be  turned,  twisting  the  liga- 
ture more  and  more  tightly,  until 

the  bleeding  stops.     Less  pressure 

will    be    required    if    a   stone   or 

a   tightly  rolled   handkerchief   is 

placed  under  the  ligature  and  over 

the  artery.     A  physician  must  also 

be  summoned  as  soon  as  possible, 

to  tie  the  artery.     With  a  wound 

in  the  leg,  the  method  of  stopping 

the  flow  is  similar.     Do  not  wait 

for  help,  or  to  send  for  anything ; 

use  whatever  is  at  hand  and  work 

quickly. 
Bleeding  from  Veins.  —  Some-    Fl^    34'  ~  SH°WING   raE 

METHOD    OF    APPLYING    A 

times  when  a  large  vein  is  cut,      LIGATURE  TO  THE  ARM. 


-Cut 


THE   CONTROL  OF  THE  BLOOD  FLOW  125 

the  blood  flows  so  rapidly  that  it  must  be  speedily 
stopped  to  save  life.  The  blood  from  a  vein  is  dark 
colored  and  does  not  flow  out  in  forcible  jets.  To  stop 
the  bleeding  a  ligature  should  be  applied,  but  it  should 
be  placed  beyond  the  cut,  leaving  the  cut  between  the  band- 
age and  the  heart.  Can  you  see  why? 

Diseases  of  the  Blood 

Pure  Blood.  —  It  must  now  be  clear  that  -it  is  im- 
portant to  keep  the  heart  strong  and  to  have  good,  pure 
blood  circulating  through  the  body.  We  sometimes 
speak  of  "  life  blood,"  and  this  term  is  a  good  one,  for 
every  action  of  the  body  depends  on  the  blood.  It  is 
frequently  said  that  a  person's  blood  is  in  bad  condition, 
and  we  hear  of  medicines  to  "  tone  up  the  blood." 
Usually  the  trouble  in  these  cases  is  not  with  the  blood 
at  all,  and  the  medicines,  if  they  have  any  value,  are 
useful  to  "  tone  up  "  the  vitality  of  the  whole  system  and 
incidentally  that  of  the  blood.  Most  "  blood  purifiers  " 
are  simply  patent  medicines  given  this  name  to  catch 
attention  and  to  get  money  from  the  unwary.  Food, 
air,  sleep,  and  exercise  are  the  real  "  blood  purifiers." 
A  class  of  troubles  called  "  blood  poisoning "  can  be 
better  considered  later.  There  are  two  diseases  asso- 
ciated with  the  blood  that  should  be  mentioned  here. 

Anaemia.  —  Sometimes  people,  especially  young  people, 
become  very  pale  and  the  skin  may  even  look  waxy; 
they  loso  their  vigor,  grow  weak,  and  are  unable  to  do 
their  ordinary  work.  The  doctor  says  they  are  anaemic. 
The  trouble  is  usually  either  that  their  blood  contains  too 
few  red  corpuscles,  or  that  the  corpuscles  contain  too  little 


126  PHYSIOLOGY   AND    HEALTH 

hemoglobin.  The  remedy  is  a  general  building  up  of 
the  body,  and  such  cases  require  the  care  of  a  physician. 
Malaria.  —  Malaria,  chills  and  fever,  fever  and  ague,  are 
different  names  for  the  same  disease ;  it  is  caused  by  tiny 
parasites  in  the  red  corpuscles  of  the  blood.  The  disease 
is  found  all  over  the  country  and,  in  fact,  in  most  parts  of 
the  world ;  it  is,  however,  most  prevalent  in  hot  climates. 
Its  most  common  symptom  is  the  appearance  of  a  chill 
followed  by  a  fever.  These  periods  come  with  regularity. 
Usually  there  is  one  "  chills  and  fever  day/7  followed  by 
a  day  in  which  the  person  feels  better ;  then  the  next  day 
he  has  another  chill  with  its  fever.  There  are  cases  in 
which  these  attacks  come  every  day  or  every  three  days. 
The  disease  is  common  around  swamps,  and  it  was  for 
a  long  time  supposed  to  be  caused  by  breathing  damp  air, 
particularly  the  night  air  of  certain  infested  localities. 

Then  physicians  studied 
the  cases,  especially  in 
places  where  numbers  of 
people  had  the  disease; 
after  many  experiments, 
the  germ  of  malaria  was 
discovered.  The  tiny 
parasite  lives  part  of  its 

FIG.  35.  —  THE  HARMLESS  MOSQUITO,         life  in  the  mosquito  and 

part  of  it  in  the  human 

blood.  When  a  mosquito  having  some  of  these  germs  in 
its  body  bites  a  person,  the  germs  are  carried  into  the 
blood,  and  unless  they  can  be  destroyed  there,  he  will 
soon  become  ill  with  malaria.  These  germs  are  carried 
by  only  one  kind  of  mosquito,  called  Anopheles  (see  Fig- 


THE  CONTROL  OF  THE  BLOOD  FLOW 


127 


FIG.  36.  —  THE  MALARIAL  MOSQUITO. 
Notice  that  the  body  and  head  lie  in  a  straight 
line.    This  is  not  true  of  the  Culex  shown  in 
Fig.  35. 


ure  36) ;  fortunately  this  kind  is  less  common  than  the 
more  harmless  one,  named  Culex  (see  Figure  35).  More- 
over, even  the  Anopheles  is  not  dangerous  unless  it  has 
previously  bitten  some  one  who  has  malaria,  and  so  has 
sucked  into  its  body  blood  containing  the  germs,  for  the 
mosquito  must  be  in- 
fected from  the  hu- 
man being. 

Malaria  can  there- 
fore be  prevented 
by  protecting  our- 
selves against  mos- 
quito bites.  Mos- 
quito nettings  at 
windows  and  doors  are  a  good  precaution.  The  destruc- 
tion of  the  breeding  places  of  the  mosquitoes  is  more 
effective,  however.  For  the  protection  of  a  family  it  is 
better  and  cheaper  to  dig  a  ditch  that  will  drain  a  stag- 
nant pool  than  to  buy  pounds  of  quinine,  as  a  medicine. 
Stagnant  water  is  the  incubator  of  the  mosquito  and  the 
rain  barrel  his  cradle ;  even  a  tin  can  may  harbor  a  host 
of  these  pests.  Pools  may  be  made  temporarily  harmless 
by  putting  kerosene  on  the  surface ;  it  will  spread  rapidly 
and  smother  the  mosquito  young  or  wigglers,  as  they  are 
called.  Rain  barrels  should  be  covered  with  mosquito 
netting,  or  turned  over  when  not  in  use  so  as  to  give  no 
opportunity  for  the  mosquitoes  to  breed  in  the  water; 
tin  cans  should  be  emptied  and  thrown  away  where  they 
can  do  no  harm.  As  fast  as  mosquitoes  disappear  malaria 
disappears  also.  No  mosquitoes  —  no  malaria.  It  is  im- 
portant to  remember  that  the  malaria  mosquito  flies  only 


I 

128  PHYSIOLOGY  AND   HEALTH 

at  night.  So  there  was  some  basis  for  people's  fear  of 
night  air,  only  they  were  fearing  the  wrong  thing.  Night 
air  is  not  injurious,  though  night  mosquitoes  are ;  and  if 
we  use  mosquito  nettings  we  may  keep  the  windows  open 
all  night  without  fear. 

Other  Diseases  Distributed  by  Insects 

Yellow  Fever.  -  -  Yellow  fever  is  not  regarded  as  a 
disease  of  the  blood ;  it  is  mentioned  here  because,  like 
malaria,  it  is  distributed  by  mosquitoes.  It  is  a  very 
serious  disease,  is  often  fatal,  and  is  found  chiefly  in 
tropical  climates.  Occasionally  it  has  been  brought  to 
our  southern  states,  producing  frightful  epidemics  and 
killing  thousands  of  people. 

A  few  years  ago  three  scientists  went  to  Cuba  to  study 
the  disease.  They  concluded  that  it  was  carried  by 
mosquitoes  and  to  test  the  truth  of  their  theory  they 
allowed  themselves  to  be  bitten  by  the  kind  of  mosquitoes 

that  they  suspected ; 
two  of  them  took  the 
disease  in  that  way, 
and  one  died  of  it. 
Later  several  others 
submitted  to  a  simi- 

FIG.  37.  —  THE  YELLOW  FEVER  MOSQUITO.       ,  .  •• 

lar  experiment,   and 

Note  the  striped  legs.    It  is  really  a  much  smaller  /.      ,-,  -, 

mosquito  than  Anopheles.  SOme     °f     theS6     als° 

died  of  the  frightful 

disease.  The  death  of  these  heroes,  as  brave  as  that  of 
soldiers  in  battle,  has  been  of  great  benefit  to  mankind ; 
it  has  shown  that  to  fight  the  mosquito  is  to  fight  yellow 
fever.  The  mosquito  that  distributes  this  disease  is  not 


THE   CONTROL  OF  THE  BLOOD   FLOW  129 

the  common  mosquito,  nor  is  it  the  one  that  carries  ma- 
laria. From  Figure  37  you  can  see  that  the  yellow  fever 
mosquito  has  striped  legs. 

To  stop  yellow  fever,  the  breeding  places  of  mosquitoes 
are  either  destroyed,  or  so  covered  that  mosquitoes  can- 
not get  into  them  to  lay  their  eggs.  The  patients,  too, 
are  guarded  from  mosquitoes,  since  it  is  only  by  biting 
a  patient  that  the  insect  obtains  the  germs  and  can  thus 
carry  the  disease.  Since  yellow  fever  has  been  fought 
in  this  way,  the  disease  has  lost  most  of  its  terror.  In 
Havana  and  in  Panama,  yellow  fever  was  always  present 
before  this  discovery,  but  now  it  has  practically  disap- 
peared. One  epidemic  which  started  in  New  Orleans  was 
quickly  stopped  after  the  people  began  to  fight  mos- 
quitoes. Since  mosquitoes  are  the  means  of  distributing 
two  most  serious  diseases,  they  ought  to  be  recognized 
as  our  deadly  enemies.  Money  spent  in  their  extermi- 
nation is  well  invested,  and  every  one  should  be  glad  to 
aid  in  the  work  of  destroying  them. 

Bubonic  Plague.  —  There  is  another  very  fatal  disease 
that  is  distributed  by  an  insect  .bite,  though  it  is  not 
specifically  a  disease  of  the  blood.  It  is  called  the 
bubonic  plague.  This  is  common  in  some  of  the  eastern 
countries,  but  as  yet  the  United  States  has  fortunately 
had  very  little  of  it.  This  disease  is  usually  distributed 
by  two  animals,  the  rat  and  the  flea.  Rats  acquire  the 
disease  from  human  beings ,  since  they  eat  all  manner  of 
foul  material  containing  human  excretions.  Then  fleas, 
which  are  common  in  the  rats'  fur,  become  contaminated 
with  the  germs  by  sucking  the  blood  of  an  infected  rat. 
If  those  fleas  later  jump  from  the  rat  to  a  human  being 


130  PHYSIOLOGY   AND    HEALTH 

and  bite  him,  the  germs  are  carried  to  him  and  so  the 
disease  is  spread.  The  successful  way  to  fight  this 
disease  is  to  exterminate  rats.  Ships  coming  to  this 
country  from  ports  where  the  disease  is  prevalent  are 
frequently  required  to  stay  at  some  distance  from  our 
docks,  and  to  land  their  cargoes  in  small  boats,  so  that  the 
rats  in  the  ship  may  not  get  ashore  and  perhaps  be  the 
means  of  starting  an  epidemic  of  the  disease. 

QUESTIONS 

1.  Why  does  a  quiet  life  lead  to  a  weak  heart? 

2.  When  do  you  think  there  would  be  a  large  supply  of  blood  in 
your  brain  ?    When  a  very  small  supply  ? 

3.  Do  you  see  why  it  is  difficult  to  study  after  eating  a  hearty  meal  ? 

4.  Will  the  temperature  of  a  person's  body  rise  when  he  runs? 
Can  you  explain  why  he  feels  so  much  warmer? 

5.  If  a  person  gets  out  of  breath  very  easily  when  walking  rapidly, 
is  the  trouble  in  the  heart,  lungs,  or  in  his  muscles? 

6.  Why  is  rubbing  the  feet  a  better  remedy  for  cold  feet  than  warm- 
ing them  at  a  stove? 

7.  Colds  are  accompanied  by  too  much  blood  in  the  lungs  or  the 
air  passages.     Can  you  tell  why  soaking  the  feet  in  hot  water  may  re- 
lieve a  cold? 

8.  Why  is  an  athlete  forbidden  to  smoke  tobacco  or  use  alcohol 
when  he  is  training  for  an  athletic  cpntest  ? 

9.  What  would  you  do  to  revive  a  person  who  has  fainted?    Ex- 
plain why  raising  the  head  is  the  worst  thing  to  do. 

10.  Why  is  bleeding  from  an  artery  more  dangerous  than  bleeding 
from  a  vein?    What  would  you  do  if  you  had  a  cut  in  the  arm  and 
found  that  the  blood  came  out  in  forcible  jets  ?    Why  would  you  need 
to  hurry? 

11.  Can  you  give  any  reason  why  people  living  near  swamps  are 
especially  liable  to  malaria  ? 

12.  If  there  were  yellow  fever  in  your  neighborhood,  how  would  you 
go  about  fighting  it? 


CHAPTER  IV 
WHAT   BREATHING  DOES 

EVERY  minute,  all  day  and  all  night,  a  person  breathes 
from  twelve  to  eighteen  times.  He  can  hold  his  breath 
at  will  for  about  a  minute,  but  not  longer,  or  he  can 
breathe  faster  for  a  while ;  but  the  time  will  come  when  the 
body  will  rebel  and  will  work  the  breathing  mechanism 
properly,  even  against  his  will.  This  shows  that  breath- 
ing is  absolutely  necessary  to  the  body. 

It  is  difficult  to  learn  much  from  watching  our  own 
breathing,  because  as  soon  as  we  think  about  it  we  stop 
doing  it  naturally.  Observing  somebody  else,  one  finds 
that  the  breath  is  drawn  in,  inhaled,  and  held  for  about 
a  second,  then  it  is  exhaled  (breathed  out) ;  then  there 
is  a  pause  of  a  second  or  two  for  rest,  before  the  process 
is  repeated.  Two  exceedingly  important  things  happen 
during  the  very  brief  time  that  the  air  is  in  the  body; 
oxygen  is  taken  out  of  the  inhaled  air,  and  another  gas, 
named  carbon  dioxid  (a  waste  product),  passes  into  it. 
The  body  must  get  rid  of  carbon  dioxid,  and  it  must  have 
oxygen  for  the  millions  of  living  cells  that  are  carrying 
on  the  work  of  life.  So  the  process  of  breathing,  called 
respiration,  is  an  exchange  of  gases  between  the  body 
and  the  outer  air. 

What  We  Breathe  With.  —  Under  ordinary  circum- 
stances breathing  goes  on  regularly  without  any  effort 

131 


132 


PHYSIOLOGY   AND    HEALTH 


on  our  part,  and  yet  nearly  all  the  organs  of  the  body  are 
directly  or  indirectly  involved  in  it.  Breathing  might 
be  said  to  be  the  main  business  of  the  nose,  the  throat, 
the  windpipe,  the  lungs,  the  diaphragm,  and  the  ribs. 

The  Air  Passages.  — 
Air  should  be  taken  in  at 
the  nostrils,  not  at  the 
mouth.  From  the  nos- 
trils it  passes  through 
the  nasal  cavities,  the 
surfaces  of  which  are  al- 
ways moist.  In  passing 
through  them,  the  air  is 
warmed,  and  much  of  the 
dust  in  it,  which  often 
holds  bacteria,  is  caught 
on  the  moist  surfaces. 
Any  one  can  prove  this 
by  vigorously  blowing  his 
nose  into  a  handker- 
chief after  he  has  been  breathing  air  that  is  full  of  dust ; 
it  will  be  seen  that  much  dust  is  thus  blown  on  to  the 
handkerchief. 

Mouth  Breathing.  —  When  one  breathes  through  the 
mouth,  the  air,  entering  more  easily,  passes  in  so  rapidly 
that  the  mouth  and  throat  can  catch  only  a  little  of  the 
dust  and  it  is  carried  on  into  the  lungs,  where  it  is  likely 
to  do  injury.  One  should  avoid  getting  into  the  habit 
of  mouth  breathing ;  even  when  walking  fast  or  running, 
one  should  always  breathe  through  the  nose.  It  may 
seem  as  though  one  could  run  better  if  one  took  in  breath 


FIG.  38.  —  A  SECTION  OF  THE  HEAD. 
The  figure  shows  the  air  passages  from  the 
nostrils  to  the  windpipe ;    the   arrows 
show  the  direction  of  the  air. 


WHAT  BREATHING  DOES 


133 


by  the  easiest  way,  but  mouth  breathing  is  easiest  only 
for  a  short  time ;  then  the  mouth  and  throat  become 
parched ;  the  runner  gets  "  distressed  "  and  perhaps  has 
to  stop  running.  No  trainer  of  an  athletic  team  will 
allow  one  of  his  runners  to  breathe  through  the  mouth. 
Frequently  train- 
ers find  that  a 
man  has  some 
little  growth  in 
the  throat  that  is 
partly  closing  the 
nasal  passages 
and  so  making 
natural  breathing 
difficult.  These 
growths  are  called 
adenoids ;  they 
are  common  and 
are  readily  re- 
moved. Any  one 
who  cannot 


FIG.  39.  —  THE  EFFECT  OF  MOUTH  BREATHING. 

Two  pictures  of  the  same  person,  showing  the  effect 
of  mouth  breathing ;  the  figure  on  the  right  being 
taken  after  the  removal  of  the  adenoids,  and  the 
correction  of  the  misshapen  jaw  which  resulted 
from  the  improper  method  of  breathing. 


breathe     easily 

when   the  mouth 

is    closed    should 

have  a  physician  examine  his  nose  and  throat,  for  mouth 

breathing  is  a  serious  menace  to  health. 

The  Windpipe.  —  From  the  nasal  passages  the  air 
goes  into  the  throat,  passing  down  behind  the  soft  palate, 
and  past  two  curious  little  sponges,  at  the  back  of  the 
mouth,  called  tonsils.  Then  it  goes  through  the  glottis, 
which  is  the  opening  into  the  windpipe  (trachea),  a  large 


134 


PHYSIOLOGY   AND   HEALTH 


air  tube  at  the  front  of  the  neck  that  connects  with 
the  lungs.  Just  back  of  that  air  tube  is  another  tube, 
the  gullet  or  esophagus,  down  which  the  food  passes  to 


FIG.  40.  —  THE  WINDPIPE  AND  LUNGS. 

One  lung  is  cut  open  to  show  the  air  passages  and   air  sacs.     At  the  top  of 
the  windpipe  is  the  larynx. 

the  stomach.  On  its  way  to  the  stomach  the  food  has 
to  go  by  the  glottis,  which  is  fitted  with  a  lid,  called  the 
epiglottis,  that  shuts  down  as  the  food  passes,  and  stays 
lifted  the  rest  of  the  time,  for  breathing.  One  of  the 


WHAT  BREATHING  DOES  135 

things  that  every  child  has  to  learn  is  that  if  he  tries  to 
laugh  and  swallow  at  the  same  time  there  is  trouble ; 
for  at  any  one  instant  the  little  epiglottis  cannot  be  both 
up  and  down,  and  if,  when  it  is  up  to  get  breath  for 
laughing,  a  bit  of  food  goes  past,  the  food  may  drop  into 
the  windpipe,  causing  one  to  choke  until  it  is  expelled. 

The  Larynx  and  the  Voice.  —  At  the  upper  end  of  the 
windpipe  there  is  an  organ  called  the  larynx  (see  Figure  40) 
within  which  the  voice  is  produced.  The  larynx  is  placed 
there  not  because  it  helps  in  respiration  but  because  the 
same  air  that  is  used  in  respiration  produces  the  voice. 
It  is  a  rather  complicated  structure  and  is  very  difficult 
to  understand.  The  chief  features  of  it  are  some  soft 
folds  of  the  walls  of  the  windpipe  which  are  called  vocal 
cords.  If  you  pick  up  between  your  fingers  the  skin  on 
the  back  of  the  hand,  you  will  get  a  good  idea  of  these 
folds.  When  we  are  simply  breathing  they  lie  flat 
against  the  sides  of  the  windpipe.  But  they  do  not 
always  lie  flat;  they  are*attached  at  their  ends  to  some 
tiny  hard  parts,  called  cartilages,  and  to  these  tiny  muscles 
are  connected. 

When  the  muscles  contract  in  the  right  way  the  folds 
are  lifted  away  from  the  walls  and  pulled  out  toward  the 
center  of  the  air  passage,  so  as  partly  to  close  it.  Then 
when  we  force  the  air  out  of  the  windpipe  it  has  to  pass 
through  the  rather  narrow  slit  that  is  left  between  the 
cords,  and  this  blast  of  air  sets  the  cords  shaking  rapidly, 
or  as  we  say,  sets  them  vibrating.  The  vibration  of  the 
cords  produces  the  tones  of  the  voice  when  we  speak  or 
sing,  somewhat  as  blowing  upon  a  blade  of  grass  held 
between  the  thumbs  produces  a  sound. 


136 


PHYSIOLOGY   AND   HEALTH 


If  we  want  to  sing  on  a  higher  note,  we  give  a  little  pull 
to  some  of  these  delicate  muscles,  and  that  stretches  the 
cords  a  bit  tighter  so  that  they  vibrate  faster.  If  we 
wish  a  lower  tone,  we  relax  the  muscles  so  that  the  cords 
slacken  and  vibrate  more  slowly.  When  you  first  tried  to 
sing  you  could  not  control  these  muscles  well  enough  to 
make  the  right  tone.  But  practice  has  made  it  easier.  A 
good  singer  has  acquired  a  most  wonderful  control  over 

these  tiny  muscles  and  is  able  to 
produce  a  great  variety  of  tones 
very  accurately.  If  we  wish  to 
speak  loudly  we  blow  a  strong 
blast  of  air  over  the  cords  ;  we 
speak  gently  when  we  blow  only  a 
feeble  blast  of  air  over  them.  If 
we  simply  wish  to  breathe  without 
using  the  voice,  we  let  the  cords 
flatten  back  against  the  sides  of 

th       }  gQ    th    t     th          do    not 

J 

vibrate  at  all  in  the  air. 
Air  Tubes  in  the  Lungs.  —  When  the  windpipe  enters 
the  chest  it  divides  into  two  forks  or  branches,  one  turning 
to  the  right  and  the  other  to  the  left  ;  each  branch,  then 
called  a  bronchus,  enters  an  irregular  shaped  elastic  bag 
which  is  called  the  lung  (right  lung  or  left  lung).  Each 
bronchus  is  a  hollow  tube  which  divides  again  and  again  un- 
til it  has  tube  branches  that  are  much  smaller  than  the 
smallest  twig  ;  each  of  these  tiny  tubes  ends  in  a  bunch  of 
small  rounded  air  sacs.  Imagine  a  hollow  tree,  with  no 
roots,  standing  with  its  trunk  up  and  its  branches  hanging 
down,  every  branch  and  twig  hollow  and  each  twig  ending 


FIG.  41.  -A  CLUSTER 
AIR  SACS. 


WHAT  BREATHING  DOES 


137 


in  a  cluster  of  leaves  which  when  blown  up  form  hollow 
bladders.  That  is  much  the  way  the  air  tubes  and  air  sacs 
hang  in  the  lungs.  They  make  the  lungs  light  and  spongy. 
The  Lungs. --The  lungs  are  well  protected  from  in- 
jury ;  they  are  inclosed  in  a  box,  called  the  chest  (thorax), 
which  has  the 
breast  bone  (ster- 
num) and  the  ribs 
on  its  front  and 
sides  to  make  it 
strong.  Figure 
42  shows  the 
chest  with  the 
lungs ;  they  need 
the  bony  bars 
around  them  be- 
cause they  cannot 
work  when  they 
are  torn  or  seri- 
ously injured.  FlG.  42._THE  CHEST  AND  LUNGS. 
Notice  how  the  The  figure  shows  the  position  of  the  lungs  in  the 
chest,  the  heart  being  represented  in.  dotted  lines, 
because  it  is  partly  covered  up  by  the  lungs. 


r  Heart 


bones  also  protect 

the     heart ;      its 

position  is  outlined  in  dotted  lines  because  the  lungs  lie 

over  the  greater  part  of  it. 

When  the  air  taken  in  through  the  nostrils  reaches 
the  countless  thousands  of  air  sacs  in  the  lungs,  it  fills 
some  of  them  more  or  less  completely.  When  the  air 
is  expelled,  the  lungs  collapse  somewhat ;  they  would 
collapse  much  more  if  the  air  were  all  expelled,  but 
there  is  a  considerable  amount  of  air  in  the  lungs  that 


138  PHYSIOLOGY   AND   HEALTH 

we  cannot  expel  no  matter  how  hard  we  try  to  empty 
them. 

Keeping  the  Air  Cells  Active.  —  The  lungs  of  a  well- 
developed  grown  person  hold  about  six  quarts  of  air; 
he  would  take  in  and  expel  about  a  pint  of  air  at  each 
respiration  if  he  was  sitting  still,  which  means  that  a 
large  number  of  air  sacs  are  not  working.  It  is  not 
necessary  or  desirable  that  all  of  these  air  sacs  should 
work  all  the  time.  There  have  to  be  enough  air  sacs  to 
do  all  kinds  of  emergency  work  that  may  call  for  very 
deep  and  rapid  breathing,  like  sprinting  or  mountain 
climbing ;  but  if  any  of  them  are  left  idle  too  long  they 
tend  to  become  useless  and  then  they  may  serve  as 
lodging  places  for  dangerous  germs.  On  the  other 
hand,  to  try  to  use  them  all  constantly  would  be  throw- 
ing a  useless  amount  of  work  on  the  lungs ;  so  the  problem 
is  to  use  them  just  often  enough  to  keep  them  in  good 
condition,  ready  to  respond  to  extra  demands  when  these 
come. 

The  best  plan  is  to  do  some  vigorous  work  every  day ; 
chopping  wood,  sweeping,  carrying  wood  and  coal,  doing 
"  chores  "  -  all  are  excellent  ways  of  distending  the  air 
sacs,  especially  if  done  briskly  and  with  spirit.  Running 
and  rapid  walking  also  serve  the  purpose,  and  people 
who  are  so  unfortunate  as  not  to  be  able  to  take  regular 
exercise  out  of  doors  may  find  a  partial  substitute  by 
taking  five  minutes,  three  times  a  day,  for  deep  breathing. 
They  should  go  to  an  open  window,  unless  the  day  is 
too  cold,  inhale  as  much  air  as  possible,  and  then  exhale 
it  as  slowly  as  possible,  trying  the  next  time  to  inhale 
still  more  air  and  to  exhale  it  still  more  slowly  and  com- 


WHAT  BREATHING  DOES  139 

pletely.  This  should  be  done  regularly,  and  with  the 
clothing  around  the  neck  and  waist  so  arranged  that  it 
does  not  limit  the  extent  to  which  the  chest  can  be  ex- 
panded. 

How  the  Blood  Is  Purified 

Blood  Vessels  in  the  Lungs.  —  The  large  blood  vessel 
(pulmonary  artery)  that  carries  the  impure  blood  from 
the  heart  to  the  lungs,  divides  when  it  enters  the  lungs 
into  small  blood  vessels  and  they  into  smaller  capillaries, 
until  the  tiny  air  sacs  of  the  lungs  look  as  though  they 
were  covered  with  a  fine  reddish  netting  (see  colored 
insert  facing  this  page).  The  walls  of  the  capillaries  are 
very  thin,  and  so  are  the  walls  of  the  air  sacs ;  in  fact, 
they  do  not  prove  any  hindrance  to  the  important  ex- 
changes that  must  take  place  between  blood  and  air 
in  order 'to  make  the  blood  fit  for  further  use.  Those 
changes  may  be  summed  up  in  two  sentences. 

What  the  air  loses  the  blood  gains. 
What  the  blood  gives  up  the  air  takes. 

Exchanges  between  Blood  and  Air.  —  Both  the  blood 
and  the  air  are  very  different  after  they  have  passed 
through  the  lungs.  The  blood  has  been  purified,  four 
important  changes  having  taken  place  in  it. 

1.  The  blood  takes  oxygen  from  the  air.  —  The  hemo- 
globin of  the  red  corpuscles  has  an  affinity  for  oxygen, 
and  fairly  snatches  it  out  of  the  air  in  the  lungs.  Then 
the  corpuscles  become  a  more  brilliant  red,  and  this 
changes  the  appearance  of  the  blood  from  bluish  red, 
which  is  the  color  of  impure  blood,  to  a  bright  scarlet. 


140  PHYSIOLOGY   AND   HEALTH 

There  is  21  per  cent  of  oxygen  in  the  air  we  inhale,  and 
the  corpuscles  take  out  nearly  one-third  of  it,. leaving  15 
per  cent  in  the  air  that  is  expelled. 

Oxygen  is  required  for  all  kinds  of  combustion.  With- 
out it  the  fire  in  the  stove  will  not  burn ;  nor  will  iron 
go  on  rusting,  for  even  this  slow,  flameless  combustion 
requires  oxygen.  Without  oxygen  the  right  amount  of 


FIG.  43.  —  COMBUSTION  REQUIRES  OXYGEN. 

The  candle  burns  if  the  top  of  the  jar  is  left  open,  so  that  the  air  can  have 
entrance.  If  the  jar  is  covered  with  a  paper,  the  candle  burns  lower  and  is 
finally  extinguished  from  lack  of  air. 

digested  fuel  food  might  be  carried  by  the  blood  to  every 
tissue  of  the  body,  and  still  the  food  would  be  of  no  use ; 
for  it  is  by  a  slow  and  flameless  kind  of  combustion  that 
the  food  is  used  in  our  bodies.  The  simple  experiment 
illustrated  in  Figure  43  shows  the  need  of  oxygen  for 
combustion.  The  candle  in  the  jar  goes  out  as  soon  as 
the  oxygen  is  used  up.  The  jar  also  becomes  filled 
with  a  new  gas,  carbon  dioxid. 

2.    The    blood   gets   rid   of   carbon    dioxid.  —  Whether 


WHAT  BREATHING  DOES  141 

combustion  takes  place  in  the  stove  or  in  the  body,  it 
produces  carbon  dioxid  gas,  and  combustion  cannot 
continue  if  that  gas  is  not  removed.  In  the  stove 
there  is  a  draft  that  carries  the  gas  up  the  chimney. 
In  the  body  the  blood  takes  the  carbon  dioxid  from  the 
tissues  to  the  lungs  ;  the  lungs  take  it  from  the  blood  and 
send  it  out  into  the  air  with  every  exhalation.  There  is 
almost  no  carbon  dioxid  in  the  air  we  breathe  in,  but 
in  the  air  we  breathe  out  there  is  a  considerable  quantity 
of  it.  In  case  the  blood  did  not  take  it  up  from  the 
tissues,  they  would  be  dulled  and  finally  poisoned  by  it, 
and  sickness  or  death  would  result. 

3.  The  blood  is  cooled.  —  During  the  greater  part  of 
the  year,  the  air  we  breathe  into  our  lungs  is  cooler  than 
the  temperature  of  the  body.     The  outdoor  air  is  often 
very  much  cooler,  and  even  in  winter  the  air  we  breathe 
indoors  is  (or  at  least  ought  to  be)  about  thirty  degrees 
cooler  than  the  body.     When  air  is  expelled  from  the 
lungs  it  is  nearly  as  warm  as  the  body  temperature 
(98.6°) ;   it  has  been  warmed  by  the  blood  in  the  lungs, 
and  of  course  the  blood  has  lost  as  much  heat  as  the  air 
gained.     This  cooling  of  the  blood  is  one  means  that  the 
body  has  of  regulating  its  temperature. 

4.  The  blood  gives  up  moisture.  —  As  a  general  rule, 
the  air  that  is  exhaled  is  nearly  saturated  with  water. 
Was  it  in  the  air  that  was  inhaled?    Test  this  by  blow- 
ing some  air  from  a  syringe  bellows  onto  a  cold  window 
pane;    then  take  a  deep  breath  and  blow  it  out  onto 
another  window  pane:    The  moisture    that    makes    the 
second  pane  cloudy  comes  from  the  blood.     This  does 
not  mean  that  the  blood  gets  too  thin  as  it  travels  around 


142 


PHYSIOLOGY   AND   HEALTH 


the  body  and  needs  to  lose  water  as  it  needs  to  lose  carbon 
dioxid.  Giving  off  moisture  in  the  lungs  is  another  one 
of  the  provisions  for  regulating  the  body  temperature. 

How  Air  Is  Drawn  into  the 
Lungs. --We  have  been 
breathing  ever  since  we  can 
remember,  so  it  does  not  seem 
strange  to  us  that  air  can 
easily  be  taken  into  the  lungs  ; 
yet  this  is  done  by  a  very 
ingenious  mechanism.  The 
hollow  air  tubes  and  sacs  of 
the  lungs  can  hold  plenty  of 
air,  but  they  are  inside  the 
body,  far  away  from  the  air ; 
air  will  fill  an  open  tube,  but 
it  will  not  keep  on  passing 
in  and  out,  just  so  many  times 
a  minute. 

A  hollow  rubber  ball  with 
a  hole  in  it  gives  a  simple 
illustration  of  the  way  in 
which  air  is  taken  into  and 
expelled  from  the  lungs.  If 


FIG.  44.  —  THORAX  VIEWED  FROM 

THE    SIDE,    AND    SHOWING  THE 

SHAPE  OF  THE  DIAPHRAGM. 
The  dotted  line  shows  the  position        ,        ,     ,,    .  ,       . , 

of  the  diaphragm  when  inhaling;      the    bal1   1S    Squeezed,    the    air 

in  it  is  forced  out.  This  will 
show  more  plainly  if  the  ball 
When  one  stops  squeezing,  the 
ball  resumes  its  former  size  and  shape,  and  as  it  does 
so,  air  to  fill  it  is  drawn  in  through  the  hole.  In  much 
the  same  way,  air  is  forced  out  from  and  drawn  into  the 


the  firm  line  shows  its  position 
when  breath  has  been  exhaled. 

is  squeezed  under  water. 


WHAT  BREATHING  DOES 


143 


lungs,  by  making  changes  in  the  size  and  shape  of  the 
chest  box  in  which  the  lungs  are  inclosed. 

The  Diaphragm  and  the  Ribs.  —  The  box  that  pro- 
tects the  lungs  is  irregular  in  shape.  The  front,  sides, 
and  top  of  it  are  well  closed  in  with  ribs,  muscles,  and 


A  B 

FIG.  45.  —  SHOWING  THE  USE  OF  THE  DIAPHRAGM. 

The  lungs  of  a  small  animal  are  attached  to  the  glass  tube  in  A,  and  when 
the  rubber  membrane  is  pulled  down,  as  shown  in  B,  air  is  sucked  in.  A 
collapsible  rubber  bag  may  be  substituted  for  the  lungs. 


skin.  At  the  back  it  is  closed  by  the  backbone  and  the 
ribs.  At  the  bottom  there  is  a  muscular  membrane,  called 
the  diaphragm,  which  extends  across  the  chest  and  com- 


144  PHYSIOLOGY  AND   HEALTH 

pletely  closes  that  end  of  the  chest  box.  When  the 
diaphragm  is  relaxed,  it  lies  in  an  upward  curve,  as  shown 
by  the  full  line  in  Figure  44.  When  the  muscles  of  the 
diaphragm  are  shortened,  it  straightens  out,  assuming 
the  shape  shown  by  the  dotted  line  in  Figure  44.  This 
makes  the  space  in  the  chest  larger  and  fresh  air  rushes 
in  to  fill  the  enlarged  space.  The  only  opening  into  the 
chest  is  through  the  windpipe  (which  serves  the  same 
purpose  as  the  hole  in  the  rubber  ball).  When  the  chest 
space  is  increased,  air  is  forced  through  the  windpipe 
into  the  lungs  (inhalation) ;  the  air  pressure  expands  the 
lungs,  and  so  the  chest  box  is  filled. 

The  mechanics  of  respiration  can  be  most  interestingly 
explained  as  the  making  and  filling  of  a  partial  vacuum. 
With  a  little  simple  apparatus  this  can  be  made  clear. 
Pass  a  glass  tube  through  the  cork  in  a  bell  glass  and 
tie  a  flexible  rubber  bag  (or  the  lungs  of  a  small  animal) 
tightly  over  the  lower  end  of  the  tube.  Close  the  mouth 
of  the  bell  glass  by  tying  a  sheet  of  rubber  over  it  very 
firmly.  When  the  rubber  sheet  is  pulled  down  into  the 
position  as  in  Figure  45  B,  a  partial  vacuum  is  produced. 
Air  rushes  in  through  the  tube  to  fill  it  and  the  bag  (or 
lungs)  attached  to  the  tube  expands. 

In  the  enlargement  of  the  chest  box,  the  diaphragm  is 
helped  by  the  ribs  to  make  the  space  within  the  chest 
larger.  In  their  usual  position,  the  ribs  bend  downward. 
When  the  diaphragm  is  lowered,  the  numerous  muscles 
surrounding  the  ribs  raise  them  upward  and  forward, 
thus  further  increasing  the  space  within  the  chest.  The 
dotted  lines  in  Figure  46  show  the  position  of  the  ribs 
when  the  lungs  are  full. 


WHAT  BREATHING  DOES 


145 


Little  or  no  muscular  effort  is  required  for  exhalation. 
After  the  lungs  are  filled  with  air,  the  muscles  of  the  ribs 
relax,  and  the  ribs  fall  of  their  own  weight  to  the  position 
shown  by  the  solid  lines  in  Figure  46.  At  the  same  time 
the  muscles  of  the  diaphragm  relax,  and  it  takes,  its 
former  position,  partly  from 
the  push  given  it  by  the 
liver,  stomach,  and  other 
abdominal  organs  that  were 
pressed  out  of  position  by 
the  diaphragm  when  it  was 
flattened  down.  So  the  mo- 
tions of  the  diaphragm  and 
the  ribs  decrease  the  size  of 
the  chest  cavity,  and  this 
squeezes  the  air  out  of  the 
lungs,  much  as  we  can 
squeeze  it  out  of  a  rubber 
ball.  The  action  of  all 
these  various  muscles  is 
controlled  by  the  brain, 
without  our  being  at  all 
conscious  of  what  is  taking 
place. 

Breathing       Correctly. FIG.  46.  —  THORAX  VIEWED  FROM  THE 

Most  babies  breathe  prop-      ^  T0  SHOW  THE  AcTION  OF  THB 
erly,  and  people  who  work    The  dotted  line  shows  the  position 

hard,  whether   at   mUSCUlar         when  we  inhale,   and  the  firm  line 
11  ...  j         the  position  at  the  end  of  exhalation. 

labor    or    in    singing    and 

speaking,  learn  to  use  their  breathing  apparatus  correctly. 

Many  of  the  rest  of  us  are  likely  to  acquire  lazy  habits 


146  PHYSIOLOGY  AND   HEALTH 

of  breathing,  or  to  have  tight  bands  around  chest  and 
waist  that  interfere  with  proper  breathing. 

There  are  two  reasons  why  the  diaphragm  and  the 
muscles  of  the  lower  ribs  should  be  used:  (1)  Without 
their  use  certain  portions  of  the  lungs  do  not  get  any 
exercise.  (2)  The  regular  movements  of  the  diaphragm 
are  found  to  assist  the  circulation  of  the  blood. 

Singers  and  public  speakers  find  that  it  is  absolutely 
necessary  for  them  to  learn  to  use  the  abdominal  muscles 
in  connection  with  the  diaphragm,  in  order  to  get  tones 
that  have  both  volume  -and  carrying  power. 

Breathlessness  and  Second  Wind.  —  Ordinarily  we 
breathe  from  12  to  18  times  a  minute ;  if  we  get  fright- 
ened or  excited,  we  breathe  more  rapidly,  and  any  vigorous 
exercise,  like  running  or  hurrying  up  stairs,  starts  rapid 
breathing.  If  one  goes  on  running,  he  gets  breathless, 
begins  to  "  pant,"  and  breathing  becomes  painful. 
Every  athlete  knows  that  when  he  begins  vigorous 
work  he  must  go  through  a  time,  longer  or  shorter,  in 
which  he  finds  it  difficult  "  to  get  breath  "  fast  enough 
for  the  rate  at  which  he  is  trying  to  work.  He  has  to  make 
a  distinct  effort  of  the  will  to  keep  up  the  pace  that  he 
has  set  for  himself  and  it  may  seem  as  though  he  could  not 
go  on.  Then,  gradually,  he  feels  stronger,  his  breath 
comes  easier,  the  thumping  of  his  heart  is  lessened,  and 
he  says  that  he  has  his  "  second  wind."  He  can  go  on 
for  some  time  with  comparative  ease.  His  distress  in 
the  beginning  is  really  not  due  to  lack  of  sufficient  breath ; 
it  is  due  rather  to  the  fact  that  the  heart  is  suddenly 
called  upon  for  much  extra  work  and  has  not  fully  re- 
sponded. 


WHAT  BREATHING  DOES  147 

When  the  heart  gets  to  beating  rapidly  enough  to 
carry  the  blood  around  as  fast  as  his  muscles  need  it, 
his  breathing  is  easier  and  he  has  his  "  second  wind." 
If  a  runner  cannot  get  his  second  wind,  it  is  not  usually 
due  to  weak  lungs  but  to  the  action  of  his  heart.  When 
he  is  properly  "  trained,"  his  heart  is  so  strengthened 
that  he  can  get  the  second  wind  quicker  and  can  work 
longer  than  the  man  who  is  not  "  in  training."  If  a 
person  continues  to  be  breathless  when  running,  it  means 
that  he  is  working  his  heart  too  hard  and  may  do  it 
permanent  injury.  He  should  stop  the  violent  exercise 
for  a  while. 

Taking  Exercise.  —  Some  forms  of  exercise  work  one 
set  of  muscles  and  some  other  sets,  but  all  of  them  also 
involve  exercise  for  the  heart  and  the  lungs.  As  soon 
as  we  begin  to  exercise  our  arms,  more  blood  runs  into 
them.  If  we  are  using  them  vigorously,  the  heart  also 
begins  to  beat  faster  in  order  to  send  the  blood  still 
more  rapidly ;  then  respiration  becomes  deeper  and  more 
rapid,  for  the  blood  is  going  to  the  lungs  more  rapidly 
and  the  changes  that  take  place  there  must  be  hastened. 

The  lungs  would  have  exercise  enough  if  one  did  vig- 
orous work  an  hour  or  so  every  day,  year  in  and  year 
out.  But  as  many  men  and  women,  when  they  are 
grown,  spend  most  of  their  lives  indoors,  it  is  most  desir- 
able that  while  young  they  should  acquire  good  lung 
capacity ;  then  if  later  their  occupation  gives  them  little 
opportunity  for  work  in  the  open  air,  they  will  still  be 
able,  with  some  systematic  breathing  exercises,  to  retain 
the  benefit  of  their  early  work.  They  will  have  strong, 
capable  lungs. 


148  PHYSIOLOGY   AND   HEALTH 

There  is  also  another  reason  why  good  lung  expansion 
should  be  gained  in  youth;  the  heart  is  then  most  ca- 
pable of  doing  the  extra  work  required  of  it.  Violent 
and  long-continued  exercise  is  not  good  for  boys  or 
girls ;  they  need  regular  and  moderate  exercise.  Lift- 
ing light  dumb-bells  is  far  better  exercise  than  lifting 
heavy  weights  that  strain  and  tire  the  muscles  and 
may  also  strain  and  weaken  the  heart,  perhaps  causing 
serious  trouble  later  on. 

The  Key  to  Health.  —  Exercise  is  really  the  key  to 
health.  It  not  only  strengthens  the  muscles  but  it 
strengthens  the  heart,  quickens  circulation,  hastens  the 
flow  of  lymph,  exercises  the  lungs,  aids  digestion,  and 
makes  the  mind  clearer  for  thinking.  With  all  these 
advantages  it  should  not  be  neglected.  Between  the 
ages  of  ten  and  twenty  young  people  can  do  a  tremendous 
amount,  by  regular  habits  of  life  and  regular  exercise, 
toward  laying  the  foundation  for  future  health  and  hap- 
piness. 

Running  has  already  been  recommended  as  excellent 
exercise.  There  are  many  boys  who  would  stand  higher 
in  their  classes  if  they  would  run  a  mile  every  day  in  the 
open  air.  For  city  boys  brisk  walking  sometimes  has  to 
take  the  place  of  running.  Swimming  is  the  best  all- 
around  exercise,  and  there  are  many  kinds  of  work  in 
doors  and  out  that  can  be  made  the  means  of  getting 
much  excellent  exercise.  The  boy  or  girl  who  lives  on  a 
farm  can  make  a  long  list  of  healthful  kinds  of  work. 
What  kinds  of  work  are  there  for  you  to  do  that  would 
help  in  the  home  and  also  give  you  some  of  the  exercise 
you  need  ? 


WHAT  BREATHING  DOES  149 

QUESTIONS 

1.  Can  you  tell  why  mouth  breathing  is  injurious? 

2.  Name  the  organs  upon  the  functioning  of  which  breathing  de- 
pends.    Describe  just  what  happens  when  we  take  in  a  breath  of  air; 
when  we  breathe  it  out. 

3.  Place  your  hand  at  your  throat.     Sing  a  few  notes,  pitching 
your  voice  first  low  and  then  high.     Explain  how  the  vibrations  that 
you  can  feel  are  produced.     Were  they  any  different  when  you  sang 
high  from  when  you  sang  low? 

4.  What  is  the  use  of  the  air  sacs  in  the  lungs?    What  effect  will 
running  have  upon  the  air  in  the  air  sacs? 

5.  What  four  changes  take  place  in  the  blood  after  it  enters  the 
lungs  ?    What  changes  take  place  in  the  air  ? 

6.  What  color  would  you  think  the  blood  of  a  person  would  be 
who  had  died  of  suffocation  ? 

7.  Do  you  think  the  blood  would  be  cooled  by  rapid  breathing  on 
a  hot  summer  day  when  the  thermometer  was  105  degrees  ? 

8.  What  effect  would  a  tight  belt  or  a  tight  corset  have  upon 
breathing  ? 

9.  What  kind  of  games  should  be  avoided  by  a  person  who  has 
difficulty  in  getting  his  "second  wind"? 

10.  Mention  all  the  advantages  you  can  think  of  that  come  from 
taking  regular  exercise. 

To  THE  TEACHER.  Have  pupils  take  each  other's  chest  measure- 
ments, noting  the  number  of  inches  of  expansion  when  a  deep  breath 
is  taken  in. 

Have  pupils  perform  the  experiment  with  the  candle  described  in 
this  chapter. 

Another  interesting  experiment  to  illustrate  how  the  air  which  we 
breathe  out  has  been  robbed  of  oxygen  is  as  follows  : 

Place  a  piece  of  cardboard  over  the  mouth  of  a  fruit  jar.  Through 
a  hole  in  the  cardboard  insert  a  glass  tube.  Breathe  through  the  tube 
in  and  out  from  the  jar  several  times.  Carefully  invert  the  jar  over  a 
lighted  candle  allowing  as  little  air  to  escape  as  possible.  The  candle 
will  not  burn,  since  the  air  has  been  replaced  with  carbon  dioxid. 


CHAPTER  V 

VENTILATION.     ARTIFICIAL   RESPIRATION 
Ventilation 

What  Ventilation  Does.  —  Out  of  doors  there  is  no 
need  for  ventilation ;  the  air  is  constantly  stirring  even 
when  there  is  no  wind,  and  the  impure  air  that  people 
exhale  is  soon  carried  away,  plenty  of  fresh  air  taking 
its  place.  Indoors,  especially  when  there  are  a  number 
of  people  in  one  room,  four  things  need  to  be  done  in 
order  to  give  every  one  wholesome  air  to  breathe  — 
notice  how  they  correspond  to  the  four  changes  that 
take  place  in  the  air  while  it  is  in  the  lungs. 

1.  Provide  a  sufficient  supply  of  oxygen. 

2.  Provide  a  current  of  air  to  take  away  the  waste  car- 
bon dioxid. 

3.  Maintain  a  proper  temperature. 

4.  Carry  off  the  exhaled  moisture. 

Record  of  Open-Air  Schools.  —  The  open-air  schools, 
started  for  pupils  who  are  required  by  their  physicians 
to  live  in  the  open  air,  winter  and  summer,  have  had 
surprising  results.  At  first  it  was  thought  that  the 
pupils  could  not  accomplish  much  in  winter,  when  they 
must  be  very  warmly  bundled  up;  but  it  was  found 
that  those  children,  clumsy  as  their  clothing  may  some- 
times be,  could  actually  do  more  studying  and  with  less 

150 


VENTILATION.      ARTIFICIAL   RESPIRATION        151 

effort  than  children  who  were  working  comfortably  in 
closed  and  heated  rooms.  There  were  not  so  many 
absences  on  account  of  headaches  and  colds,  and  the 
pupils  did  not  have  those  heavy,  dull  feelings  that  so 
often  come  to  indoor  pupils  at  the  end  of  the  morning's 
work.  In  those  schoolrooms,  nature  is  allowed  to  attend 
to  the  first,  second,  and  fourth  of  the  requirements  listed 
above ;  and  proper  temperature  is  secured  by  wearing 
clothing  so  warm  that  the  body  heat  is  easily  maintained. 

What  Happens  to  the  Air  Indoors.  —  Most  people  live 
and  study  in  homes  and  schoolrooms  from  which  the  out- 
door air  must  be  largely  excluded  in  winter,  and  in  which 
artificial  heat  is  also  required. 

We  know  that  if  any  large  amount  of  breathed  air 
accumulates  in  a  room  the  odor  becomes  unpleasant 
and  the  effect  is  unwholesome.  Those  who  are  sitting 
in  the  room  may  not  notice  that  the  air  has  become 
"  bad  "  ;  but  let  the  pupils  go  out  for  recess  and  if  the 
schoolroom  is  not  properly  ventilated,  it  will  seem  close 
when  they  come  in.  Such  an  unpleasant  odor  in  a  room 
means  that  the  air  is  unwholesome  to  breathe  and  will  be 
likely  to  make  those  sitting  there  drowsy  and  to  give 
them  headaches.  •  • 

How  Air  Gets  "  Close."  -  It  is  not  enough,  however, 
to  know  that  a  "  close  "  room  is  unwholesome ;  we  want 
to  know  what  makes  the  air  "  close."  On  this  point  a 
great  many  interesting  experiments  have  been  made. 
Persons  have  been  shut  up  in  large,  tightly  sealed  boxes 
into  which  air  could  be  pumped  at  will.  It  has  been 
found  that  if  care  is  taken  to  extract  the  carbon  dioxid 
from  the  breathed  air,  and  to  put  in  more  oxygen  to 


152  PHYSIOLOGY   AND   HEALTH 

take  the  place  of  that  used  in  the  lungs,  a  man  can  com- 
fortably remain  in  such  a  box  for  days;  that  there  are 
no  unpleasant  results  from  being  confined  in  such  a  box 
if  the  air  is  kept  cool  and  is  not  allowed  to  get  too  moist. 

In  other  tests,  people  have  been  kept  in  small  rooms 
in  which  they  could  m.ove  around  and  work  comfortably, 
the  rooms  being  so  arranged  that  the  air  could  be  made 
hot  or  cold,  wet  or  dry,  pure  or  impure.  Many  facts 
have  been  learned  from  these  tests.  It  has  been  shown 
that  to  keep  the  air  fresh  and  sweet,  at  least  four  things 
are  needed.  The  carbon  dioxid  must  be  removed; 
the  air  must  not  be  allowed  to  become  warm ;  the  air 
must  not  be  allowed  to  become  too  moist  or  too  dry; 
various  dirt  or  dust  particles,  which  come  from  people's 
clothes  or  elsewhere,  must  be  removed.  Each  of  these 
requirements  may  be  met  in  various  ways,  but  the  one 
most  readily  applied  everywhere  is  to  arrange  to  keep  a 
current  of  fresh  air  entering  the  room  and  to  have  it 
properly  warmed.  Hence  most  attempts  to  ventilate 
a  room  aim  at  supplying  it  with  an  abundant  amount  of 
outdoor  air. 

How  Rooms  Are  Ventilated.  —  The  ventilation  of  large 
buildings  is.  a  scientific  and  engineering  problem  which 
has  no  place  here.  What  we  want  to  consider  is  how 
to  keep  the  air  pure  and  fresh  in  our  homes  and  in  school- 
rooms and  other  assembly  rooms  where  apparatus  for 
ventilation  cannot  be  installed.  In  such  places  the 
problem  of  ventilation  is  practically  solved  if  the  used 
air  can  be  caused  to  pass  out,  for  the  excess  heat  and 
moisture  are  then  carried  off.  In  an  ordinary  room, 
sufficient  fresh  air  will  come  in  around  the  windows 


VENTILATION.      ARTIFICIAL  RESPIRATION        153 

and  doors  if  there  is  only  some  adequate  provision  for 
carrying  off  the  used  air.  Figure  47  shows  the  direc- 
tion taken  by  the  air  currents.  To  ventilate  a  room 
properly  we  must  therefore  provide  an  exit  for  the  heated 
air  that  rises  to  the  top  of  the  room  and  also  for  the 


FIG.  47.  —  AIR  CURRENTS  IN  A  ROOM. 

The  direction  of  the  air  currents  in  an  ordinary  room  are  shown 
by  the  arrowheads. 

heavy  air  (heavy  with  carbon  dioxid)  which  tends  to 
sink  toward  the  floor. 

In  a  room  occupied  by  many  people,  like  a  schoolroom, 
the  air  is  used  up  more  rapidly,  and  frequently  cracks 
around  doors  and  windows  do  not  let  the  used  air  out 
fast  enough,  and  so  sufficient  fresh  air  does  not  come  in. 
Then  some  other  means  are  necessary.  One  of  two 
things  may  be  done:  either  make  more  of  the  used  air 
go  out,  or  make  the  fresh  air  come  in  enough  faster  to 
force  the  bad  air  out. 

Usually  it  is  easier  to  take  the  second  method.     One 


154  PHYSIOLOGY   AND   HEALTH 

of  the  simplest  ways  of  doing  this  is  to  raise  the  lower 
sash  of  the  windows  with  a  solid  board  six  or  eight  inches 
wide  fitted  close  to  the  window  frame.  Air  will  then 
enter  the  room  through  the  space  between  the  win- 
dow sashes,  and  as  it  starts  upwards  it  will  not  fall 
upon  those  sitting  near  the  window.  A  series  of  holes 
bored  through  the  board  will  admit  more  air  if  needed, 
and  these  may  be  easily  fitted  with  plugs  to  fill  them 
when  there  is  intense  cold  or  a  high  wind. 

Heating  and  Ventilation.  —  In  cold  climates  it  is 
necessary  to  heat  rooms  in  winter.  Some  methods  of 
heating  a  room  help  to  ventilate  it  and  some  make  venti- 
lation more  difficult.  A  room  heated  with  a  stove  or  a 
fireplace  is  easily  ventilated,  for  a  burning  fire  causes 
a  continuous  draft  up  the  chimney;  this  draft  removes 
air  from  the  room,  and  fresh  air  always  rushes  in  to 
replace  it.  If  the  stove  is  allowed  to  get  too  hot  it 
makes  the  room  overwarm,  and  then  the  people  there 
feel  uncomfortable,  even  though,  because  of  the  draft 
made  by  the  rapidly  burning  fire,  an  unusual  amount  of 
fresh  air  is  constantly  coming  into  the  room.  That 
trouble  may  be  remedied  by  putting  around  the  stove  a 
jacket  (Figure  48)  connected  by  a  pipe  with  the  outer 
air;  in  this  way  fresh  air  will  be  sucked  into  the  jacket, 
and  thus  into  the  room,  fast  enough  to  prevent  the 
room  from  getting  so  hot  as  to  be  uncomfortable. 

In  houses  heated  by  hot-air  furnaces  special  devices  are 
commonly  adopted  for  supplying  fresh  air.  The  furnace 
is  connected  with  what  is  called  the  cold  box,  which  is 
open  to  the  outdoor  air.  The  air  enters  this  box,  passes 
into  the  furnace,  is  there  heated,  and  then  hot,  fresh 


VENTILATION.      ARTIFICIAL  RESPIRATION        155 

air  rises  through  the  flues  into  the  different  rooms.  Open 
ventilating  flues  in  the  chimney  help  to  get  rid  of  the 
impure  air.  Furnace-heated  air.  is  apt  to  be  too  dry, 
especially  in  very  cold  weather.  If  there  are  no  evaporat- 
ing pans  in  the  furnace,  some  open  jars  of  water  standing 


FIG.  48.  —  A  JACKETED  STOVE. 

A  stove  with  such  a  jacket  around  it  draws  fresh  air  from 
the  outside  and  distributes  it  through  the  room.  The 
air  passes  in  the  direction  of  the  arrowheads. 

about  the  room  will  make  the  air  more  comfortable  by 
increasing  the  amount  of  moisture. 

In  houses  heated  by  steam  radiators  it  is  not  so  easy  to 
keep  the  air  pure ;  for  although  currents  of  air  move  up 
and  down  the  room,  they  do  not  readily  pass  out.  We 
must  then  depend  upon  other  means  for  bringing  in  fresh 
air,  such  as  partly  open  windows,  or  flues,  or  fireplaces. 


156  PHYSIOLOGY   AND   HEALTH 

The  "  closeness  "  or  "  stuffiness  "  of  steam-heated  rooms 
may  be  remedied  if  we  can  find  some  way  of  keeping  the 
air  in  motion.  On  a  hot  summer  day  we  feel  comfortable 
if  there  is  a  breeze,  while  if  the  breeze  disappears  we  begin 
at  once  to  suffer  from  the  heat.  Even  on  a  hot  day  the 
bicycle  rider  feels  cool  as  long  as  he  keeps  moving  but 
becomes  very  hot  the  moment  he  stops  riding.  Even  an 
overheated  room  or  one  occupied  by  many  people  generally 
feels  comfortable  if  the  air  can  be  kept  moving,  but  if  the 
air  becomes  stagnant,  the  room  is  uncomfortable  at  once. 

Comfort  in  Public  Halls.  —  In  a  schoolroom  or  a  public 
hall,  where  numbers  of  people  are  gathered,  the  air  is 
almost  sure  to  become  unfit  for  breathing  unless  special 
means  are  used  to  secure  good  ventilation.  It  has  been 
discovered  that  unpleasant  feelings  may  be  almost  en- 
tirely prevented  by  keeping  the  temperature  down 
below  65°.  Nowadays  large  school  buildings  and 
assembly  halls  are  frequently  equipped  with  special 
ventilating  apparatus,  consisting  in  part  of  fans  that 
keep  the  air  circulating,  and  of  various  appliances  for 
cooling  the  air  and  for  maintaining  the  right  amount  of 
moisture  in  it.  Remember  that  there  is  little  danger  to 
well  people  from  cold,  fresh  air ;  for  every  one  who  suffers 
from  too  much  cold  air  there  are  thousands  of  people 
suffering  from  breathing  impure  air. 

Air  in  Sleeping  Rooms.  —  There  are  many  people 
whose  work  requires  them  to  spend  their  days  indoors, 
but  there  is  nothing  to  hinder  their  spending  their  nights 
in  air  that  is  fresh  and  clear.  It  used  to  be  thought  that 
night  air  was  dangerous  for  delicate  persons ;  now  we 
know  that  they  are  the  ones  who  need  most  to  breathe 


VENTILATION.      ARTIFICIAL   RESPIRATION         157 


clear,  invigorating  air  while  they  are  asleep.  A  sleeping 
room  out  of  doors,  on  a  veranda  or  porch,  has  brought 
many  an  invalid  back  to  health.  Those  who  do  not 
need  or  desire  to  sleep  out  of  doors  should  open  their 
windows  at  night. 
In  mild  weather 
the  w.i  n  d  o  w  s 
should  be  wide 
open,  half  way 
down  from  the 
top,  half  way  up 
from  the  bottom ; 
in  the  coldest 
weather  open  at 
least  a  foot,  top 
and  bottom.  In 
summer  the  win- 
dows or  the  beds 
should  be  screened 
to  protect  the 
sleepers  from  mos- 
quitoes. In  winter 
one's  bed  should 
be  so  placed  that  the  cold  air  from  the  window  will  not 
fall  directly  on  it ;  then  with  plenty  of  covering  one  can 
"  sleep  warm,"  breathe  good  cold  air,  and  wake  re- 
freshed. If  one  goes  into  a  poorly  ventilated  sleeping 
room  in  the  morning,  he  will  notice  a  close  "  body  smell," 
which  shows  that  there  was  not  sufficient  circulation  of 
air  during  the  night ;  but  he  will  not  notice  this  if  the 
room  has  been  well  ventilated. 


FIG.  49.  —  A  SLEEPING  PORCH. 


158  PHYSIOLOGY   AND   HEALTH 

Dust  Our  Enemy.  —  Our  lungs  were  meant  for  air,  not 
for  dust.  Every  one  has  seen  dust  blowing  in  the  streets 
on  a  windy  day  and  experienced  the*  discomfort  of  breath- 
ing it.  In  all  our  rooms,  even  when  we  do  not  realize 
it,  the  air  is  filled  with  dust.  Did  you  ever  notice  how 
you  can  follow  a  ray  of  light  from  a  crack  in  a  blind,  and 
how  easily  you  can  trace  it  across  the  room?  What  you 
really  see  are  tiny  particles  of  dust  floating  in  the  air. 
This  dust  is  partly  living  and  partly  lifeless,  the  living 
part  being  mostly  germs,  of  one  kind  or  another,  some 
of  them  dangerous,  most  of  them  harmless.  It  is  esti- 
mated that  a  quarter  of  a  million  people  die  in  this 
country  each  year  from  diseases  that  affect  the  respira- 
tory organs  and  that  twice  as  many  are  ill  of  the  same 
diseases.  Most  of  these  are  germ  diseases  and  some  of 
them  come  from  the  dust  of  the  air.  This  being  the 
case,  it  is  clear  that  dust  is  an  enemy  against  which  we 
should  continually  fight. 

Removal  of  Dust.  —  Not  only  should  the  streets  be 
kept  well  watered,  but  our  rooms  should  be  properly 
cared  for,  living  rooms  at  home  and  schoolrooms  as  well. 
Clearly  the  dust  should  be  removed  from  the  surfaces 
where  it  has  settled,  and  this  should  be  done  without 
stirring  it  up  and  getting  it  into  the  air  again.  Sweep- 
ing with  a  broom  and  dusting  furniture  with  a  feather 
duster  throws  the  dust  into  the  air,  from  which  it  only 
settles  back  on  the  chairs,  tables,  or  desks.  The  best 
method  of  sweeping  is  with  a  vacuum  cleaner,  for  this 
sucks  the  dirt  up  instead  of  distributing  it.  A  carpet 
sweeper  is  not  so  good  as  a  vacuum  cleaner,  but  it  is 
better  than  a  broom. 


VENTILATION.      ARTIFICIAL  RESPIRATION        159 

Wood  floors  should  be  wiped  up  with  a  damp  cloth  or 
mop,  not  swept  with  a  broom  or  covered  with  water 
which  will  take  a  long  time  to  dry  off.  An  "  oil  mop  " 
will  also  pick  up  the  dirt  without  distributing  it.  Dust- 
ing should  be  done  with  a  cloth  that  is  damp  enough  to 
hold  the  dust  without  leaving  any  moisture  on  the  sur- 
face dusted ;  for  polished  furniture  a  good  duster  may  be 
made  by  putting  a  few  drops  of  furniture  polish  on  a 
soft  cloth.  A  room  is  well  dusted  when  the  dust  is 
taken  out  of  it  on  the  duster,  not  when  the  dust  is 
brushed  off  into  the  air. 

Scientific  Dusting. -- You  may  wonder  whether  the 
results  of  dusting  and  sweeping  in  this  way  are  worth 
the  extra  trouble  required ;  but  you  could  not  get  any 
of  those  who  have  taken  part  in  schoolroom  experiments 
to  doubt  it.  In  some  schools  pupils  have  agreed  to 
give  this  subject  a  thorough  test  by  taking  care  of  their 
own  schoolrooms  in  the  approved  manner;  the  results 
reported  are  conclusive.  In  one  section  the  number  of 
colds  and  slight  occasional  illnesses  among  the  pupils 
was  reduced  by  50  per  cent.  The  same  improvement 
could  be  made  in  the  health  of  families  if  dust  were  re- 
garded as  an  enemy,  harmless  as  long  as  it  is  not  dis- 
turbed, but  so  easily  roused  that  great  care  must  be 
taken  in  its  removal.  It  is  evident  why  any  occupation 
which  keeps  one  at  work  in  a  room  constantly  filled  with 
dust  is  classed  as  a  dangerous  occupation. 

Artificial  Respiration 

In  cases  of  drowning  and  of  gas  poisoning,  respiration 
often  ceases  before  the  heart  stops  beating ;  it  may  then 


160 


PHYSIOLOGY   AND    HEALTH 


be  possible  to  save  life  by  artificial  respiration,  that  is, 
by  having  another  person  work  the  breathing  mechanism 
until  normal  respiration  can  be  resumed.  When  a  man 
has  been  too  long  under  water,  his  lungs  become  filled 
with  water  so  that  even  when  he  is  removed  from  the 
water  he  cannot  take  air  into  them.  To  save  his  life 
one  must  first  get  water  out  of  his  lungs  as  quickly  as 

possible,  and  then  get 
air  into  them.  By  all 
means  send  for  a  physi- 
cian, and  for  blankets, 
if  there  are  others  at 
hand  to  be  sent.  But 
wait  for  nothing;  go  to 
work. 

First  Aid  to  the 
Drowning. — Work  fast; 
keep  cool;  don't  give  up: 
these  are  the  watch- 
words that  should 
govern  the  effort  to 
bring  back  to  life  one 
who  has  apparently 
been  drowned.  The 
instant  that  the  drowning  man  is  brought  to  land  (or  is 
taken  into  the  boat),  raise  the  body  by  the  waist,  letting 
the  head  hang  down,  so  that  the  water  may  run  out  of 
the  mouth  and  throat.  If  it  does  not  run  out  freely,  the 
tongue  has  fallen  back.  Another  person  should  then  pull 
it  forward ;  or  if  there  is  nobody  else  near  by,  lay  the 
body  over  your  knee,  head  down,  catch  hold  of  the  tongue 


FIG.  50.  —  THE  POSITIONS  ASSUMED  IN 
ARTIFICIAL  RESPIRATION. 


VENTILATION.      ARTIFICIAL  RESPIRATION        161 

and  hold  it  down,  while  you  shake  the  body  as  much  as 
your  position  will  admit.  Not  more  than  a  minute  from 
the  time  of  leaving  the  water  ought  to  be  used  in  these 
operations,  for  the  body  is  perishing  for  lack  of  air. 

How  to  Restore  Breathing.  —  There  are  several  differ- 
ent methods  of  restoring  breathing.  One  which  can  easily 
be  carried  out  without  special  apparatus  is  as  follows: 
Place  the  patient  with  his  back  uppermost,  and  with 
the  head  slightly  turned  to  one  side.  Some  object,  like 
a  rolled-up  coat,  should  be  placed  under  his  shoulders 
so  as  to  raise  them  slightly,  thus  allowing  any  water 
that  may  be  left  in  the  lungs  to  run  out  of  the  mouth  or 
the  nostrils. 

Place  yourself  to  one  side  of  him,  as  shown  in  Figure 
50,  and  put  your  hands,  with  fingers  stretched  out,  on 
the  small  of  his  back,  with  your  two  thumbs  near  the 
back  bone  and  the  fingers  stretched  out  over  the  sides, 
just  below  the  ribs.  Throw  your  weight  upon  your  hands, 
at  the  same  time  pressing  upwards  a  little  toward  the 
patient's  head.  The  effect  of  this  sudden  pressure  will 
be  to  force  the  organs  of  the  abdomen  up  against  the 
diaphragm  and  also  to  push  the  ribs  upward  a  little. 
This  will  squeeze  some  air  out  of  the  patient's  lungs :  it 
is  an  approach  to  exhalation.  Just  as  soon  as  you  have 
fully  exerted  this  pressure,  quickly  release  it  by  throwing 
your  body  back  enough  to  remove  all  pressure  upon  your 
hands.  The  diaphragm  and  ribs  will  then  assume  their 
former  positions,  and  this  will  cause  a  little  air  to  be 
sucked  into  the  lungs  :  this  is  an  approach  to  inhalation. 

These  two  motions  should  be  kept  up  rhythmically 
about  twenty  times  a  minute,  or,  if  you  count  rather 


162  PHYSIOLOGY   AND   HEALTH 

slowly,  about  once  every  three  counts.  A  second  person 
may  help  by  lifting  the  patient's  arms  over  his  head  at 
the  time  you  relax  the  pressure,  and  lowering  them  when 
you  give  the  pressure.  In  it  all,  remember  that  what 
you  are  trying  to  do  is  to  squeeze  all  possible  air  out  of 
the  lungs  when  you  give  the  pressure,  and  then  to  allow 
the  free  expansion  of  the  chest  by  releasing  the  pressure. 

Artificial  breathing  should  be  kept  up  for  two  hours 
unless  natural  breathing  starts  earlier.  Stop  the  arti- 
ficial breathing  every  few  minutes  and  hold  some  very 
light  object,  like  a  feather  or  a  thread  unraveled  from  a 
handkerchief,  in  front  of  the  patient's  nostrils.  If  the 
object  moves,  it  indicates  natural  breathing.  Discon- 
tinue the  artificial  breathing  just  as  soon  as  this  occurs. 
Wrap  the  person  in  warm  clothing  or  in  blankets,  and 
nature  will  complete  the  restoration ;  it  will  be  an  aid 
if  the  extremities  of  the  patient  are  rubbed  during  the 
whole  process.  Persons  who  have  been  under  water 
for  a  quarter  of  an  hour,  and  even  longer,  have  been 
brought  back  to  consciousness  by  such  means. 

Other  Forms  of  Suffocation.  —  The  same  process 
should  be  used  whenever  a  person  becomes  suffocated 
from  any  cause  whatever.  If  one  has  been  overcome 
by  smoke  or  by  illuminating  gas,  artificial  respiration 
is  the  only  means  of  resuscitating  him.  A  special  kind 
of  apparatus  called  a  pulmotor  is  sometimes  used  for  this 
purpose.  If  there  is  one  to  be  had,  by  all  means  send 
for  it,  but  meantime  go  to  work  by  the  method  above 
described. 

Gas  poisoning  differs  from  suffocation  by  water  in  that 
the  gas  produces  harmful  changes  within  the  body  — 


VENTILATION.      ARTIFICIAL  RESPIRATION        163 

while  the  water  merely  prevents  breathing.  There  is  a 
substance  in  illuminating  gas  that  is  even  more  attractive 
than  oxygen  to  the  hemoglobin  of  the  red  blood  cor- 
puscles. So  these  oxygen  carriers  take  up  that  sub- 
stance, thus  leaving  the  body  to  die  for  lack  of  oxygen. 
Even  plenty  of  fresh  air  will  not  arrest  the  process  if  it 
has  gone  far,  because  the  corpuscles  that  have  taken  on 
this  foreign  substance  are  so  changed  by  it  that  they 
cannot  carry  oxygen  any  more. 

QUESTIONS 

1.  What  four  things  should  be  provided  for  in  ventilating  a  room? 

2.  Is  provision  made  for  these  four  needs  in  your  schoolroom? 
How?    Are  they  provided  for  in  your  home?     How? 

3.  Account  for  the  fact  that  pupils  in  outdoor  schools  can  study 
with  less  effort  than  children  indoors. 

4.  What  part  of  a  room  does  breathed  air  usually  occupy? 

5.  Why  is  it  not  the  best  way  to  ventilate  a  room  by  simply  throw- 
ing up  the  lower  sash  as  high  as  we  can? 

6.  How  is  a  room  with  a  stove  better  ventilated  than  a  room  with 
a  radiator  ? 

7.  During  what  season  of  the  year  are  we  likely  to  get  the  least 
amount  of  fresh  air?     Is  sickness  especially  prevalent  at  this  season? 
Can  you  see  why  ? 

8.  What  is  the  usual  temperature  of  your  schoolroom?    Of  your 
home? 

9.  Describe  a  device  which  will  enable  one  to  have  a  window 
open  on  a  cold  day  without  causing  discomfort  to  those  who  sit  near 
it.     Could  you  make  a  ventilator  of  this  sort? 

10.  Is  a  boy  who  spends  most  of  his  play  time  in  a  moving-picture 
theater  likely  to  have  as  good  health  as  one  who  spends  it  out  of  doors  ? 

11.  How  many  windows  has  your  sleeping  room?     How  much  do 
you  open  them  at  night?     If  you  share  your  room  with  some  one, 
would  you  need  to  open  the  windows  wider  than  when  you  have  a 
room  to  yourself? 


164  PHYSIOLOGY   AND   HEALTH 

12.  If  the  air  in  a  room  feels  dry,  how  can  you  remedy  it? 

13.  Find  out,  if  you  can,  how  bees  change  the  air  in  their  hives 
when  it  becomes  impure.     (Consult  an  encyclopedia.) 

14.  Give  several  reasons  why  we  have  to  give  more  attention  to 
the  problem  of  ventilation  than  did  the  early  settlers  in  this  country. 

15.  Do  you  know  any  families  who  keep  the  rooms  in  which  they 
live  at  about  80  degrees  most  of  the  time  in  winter?     Are  the  people 
who  live  in  such  homes  strong  and  well,  or  are  they  sickly?    Explain 
why. 

16.  What  have  you  noticed  about  the  air  in  some  of  the  large 
department  stores  in  the  city?     Does  your  mother  often  come  home 
with  a  headache  after  she  has  been  shopping  all  day?    What  do  you 
think  is  the  reason? 

17.  Which  has  the  more  need  to  open  his  windows  at  night,  an 
express  driver  or  a  clerk  in  a  store?    Why? 

18.  Mention  several  occupations  that  are  dangerous  because  of 
dust. 

19.  What  is  the  best  way  to  sweep  a  room?    To  dust  it? 

20.  What  would  you  do  if  you  were  alone  with  some  one  who  had 
been  so  long  under  water  that  he  had  ceased  to  breathe?    How  long 
would  you  continue  to  work  over  him  before  you  gave  up  ? 

21.  What  would  you  do  if  you  found  some  one  lying  unconscious 
in  a  room  where  the  gas  was  turned  on? 


CHAPTER  VI 
SOME   OF   THE   NATION'S   UNSEEN   FOES 

A  New  Conflict.  —  There  are  many  stories  about  the 
great  animal  monsters  who  lived  on  earth  in  the  early 
ages.  They  were  so  large  and  so  powerful  that  it  seems 
incredible  that  the  human  race,  with  its  primitive  weapons, 
should  have  survived  the  conflict  with  such  creatures. 
To-day,  few  men  are  obliged  to  fight  for  their  lives  with 
ferocious  animals;  the  scene  of  the  warfare  has  shifted. 
Mankind  has  learned  how  to  hold  in  check  the  wild 
animals  that  are  unfriendly  to  it.  New  foes  have,  how- 
ever, been  discovered ;  and  these,  as  we  saw  in  Chapter 
XII  (Section  I)  are  much  more  numerous  than  the  old 
enemies  and  even  more  dangerous  than  they,  because 
unseen  and  also  unknown  to  vast  numbers  of  people, 
who  instead  of  fighting  them  often  ignorantly  assist  them. 

These  germ  foes  of  ours  are  really  old  residents  of  the 
world.  Our  ancestors  suffered  from  them,  but  could  not 
fight  them  because  they  knew  nothing  about  them. 
Conditions  of  life  were  different  then,  for  people  were  more 
scattered;  now  a  large  portion  of  the  population  is 
crowded  together  into  cities  and  towns,  and  this  crowding 
together  makes  necessary  a  vigorous  and  incessant  com- 
bat against  our  tiny  unseen  enemies. 

Germs  a  National  Foe.  —  The  success  and  the  main- 
tenance of  a  nation  depend  less  upon  its  laws  and  its 

165 


166  PHYSIOLOGY   AND   HEALTH 

wealth  than  upon  the  integrity,  the  stamina,  and  the 
health  of  its  people.  How  can  a  nation  succeed  if  its 
people  do  not?  What  can  be  hoped  for  a  nation  if  its 
citizens  are  too  indifferent,  or  too  careless,  to  fight  vigi- 
lantly against  foes  which  in  a  single  year  incapacitate  a 
million  of  its  citizens,  killing  many  and  making  others  un- 
able because  of  illness  to  do  profitable  work?  Such  is 
the  record  of  the  germ  enemies  that  attack  the  organs 
of  respiration.  These  germs  were  not  known  until  the 
end  of  the  last  century ;  the  methods  of  fighting  them 
are  newer  still.  If  every  young  person  who  is  now  in 
school  would  do  his  share  to  stamp  out  these  enemies, 
countless  lives  and  much  wealth  would  be  saved.  It 
would  amount  to  adding  something  like  half  a  million 
people  to  our  population  each  year.  Can  you  not  see 
that  the  nation  would  be  greatly  strengthened? 

There  are  other  germs  to  fight  besides  those  that 
attack  the  respiratory  organs,  but  none  that  begin  to 
incapacitate  so  many  people;  and  there  is  no  set  of 
organs,  except  the  heart,  upon  whose  activity  we  are  so 
constantly  dependent.  We  can  live  several  days  with- 
out drinking  and  many  days  without  eating,  but  we  die 
in  a  few  moments  if  we  cannot  breathe.  For  this  reason 
anything  that  affects  the  action  of  the  respiratory  organs 
is  serious,  and  all  possible  means  should  be  taken  to  pre- 
serve them  from  injury. 

Incubation  Time.  —  After  the  germs  of  a  disease 
succeed  in  getting  into  one's  body,  several  days  pass 
before  they  produce  any  noticeable  effect.  During 
this  period  the  forces  of  the  body  are  battling  with  the 
germs  trying  to  drive  them  out ;  this  period  is  called  the 


SOME  OF  THE  NATION'S  UNSEEN  FOES  167 

incubation  period.  During  it  the  person  feels  as  well 
as  ever ;  and  if  the  germs  are  defeated,  he  may  never 
know  that  he  was  attacked  by  them.  The  incubation 
period  varies,  with  different  diseases,  from  one  day  to 
three  or  four  weeks ;  for  most  of  the  germ  diseases  it  is 
about  two  weeks. 

Three  Minor  Diseases.  —  Mumps  is  not  a  serious 
disease.  It  is  usually  confined  to  children  and  in  or- 
dinary cases  lasts  only  a  few  days.  The  glands  of  the 
cheek  and  jaws  become  swollen  and  painful,  making  it 
difficult  to  swallow.  Patients  should  be  kept  from 
school  until  well  and  for  a  few  days  after.  To  avoid 
the  disease  one  must  keep  away  from  those  who  have  it. 

Tonsillitis  is  accompanied  by  sore  throat  and  fever,  it 
usually  lasts  only  a  few  days,  and  it  is  painful  though  not 
very  serious.  The  germ  that  causes  it  is  not  known; 
it  is  probably  carried  in  the  discharges  from  the  mouth 
and  nose.  The  best  way  to  avoid  it  is  to  keep  away 
from  those  who  are  ill. 

Whooping  Cough  is  a  disease  whose  chief  symptom  is  a 
violent  cough  which  lasts  a  number  of  weeks.  It  is 
caused  by  a  germ  that  lodges  in  the  windpipe  and  pro- 
duces a  constant  irritation  which  results  in  the  spasmodic 
cough.  The  disease  is  certainly  a  contagious  one,  and 
the  germs  are  in  the  moisture  that  is  in  the  mouth  and 
nose,  so  they  are  thrown  out  into  the  air  when  the  patient 
coughs.  Any  one  who  inhales  the  air  filled  with  this 
germ-laden  moisture  is  likely  to  become  infected,  and 
thus  the  disease  passes  from  person  to  person.  The  only 
protection  is  to  avoid  being  close  to  patients  while  they 
are  coughing.  As  long  as  the  cough  continues  the  disease 


168  PHYSIOLOGY   AND   HEALTH 

remains  contagious.  Life  in  the  open  air  is  the  best 
thing  for  the  patient,  and  for  others  who  wish  to  avoid 
the  disease.  Whooping  cough  is  dangerous  for  little 
babies  and  for  old  people.  People  do  not  commonly 
have  it  a  second  time,  although  old  people  occasionally 
take  it,  even  though  they  may  have  had  it  when  children. 

Diphtheria.  —  Diphtheria  is  a  much  dreaded  disease 
which  is  usually  confined  to  children.  It  is  caused  by  a 
germ  (see  Figure  25)  that  grows  in  the  throat.  The 
first  evidence  of  it  is  usually  a  sore  throat,  with  white 
spots  on  the  tonsils.  These  spots  spread  until  a  mem- 
brane is  formed  which  grows  down  into  the  throat  and  oc- 
casionally shuts  off  the  breathing.  Ordinarily,  however, 
the  danger  is  not  from  the  membrane  itself,  but  from  a 
poison  that  is  made  by  the  diphtheria  germs  as  they  grow. 
The  poison  is  absorbed  through  the  walls  of  the  throat 
into  the  patient's  blood ;  then  the  fight  begins. 

The  poison  that  the  germ  makes  is  called  a  toxin.  The 
body,  when  attacked  by  the  diphtheria  toxin,  makes  a 
substance  called  an  antitoxin  that  neutralizes  the  effect 
of  the  poison.  If  the  body  can  make  this  antitoxin  faster 
than  the  germs  produce  the  toxin,  the  patient  will  prob- 
ably live.  To  assist  the  body,  physicians  now  administer 
a  form  of  antitoxin  that  is  produced  in  the  blood  of  specially 
selected  horses.  If  this  is  given  very  early  in  the  disease 
before  the  poison  has  weakened  the  system,  the  patient 
has  an  excellent  chance  of  recovery;  for  if  the  poison  is 
neutralized,  the  body  can  drive  off  the  germs.  Since  it  is 
so  important  that  the  antitoxin  should  do  its  work  early, 
cases  of  sore  throat  in  young  people  should  be  inspected 
by  a  physician,  especially  if  there  are  white  patches. 


SOME  OF  THE  NATION'S  UNSEEN  FOES  169 

How  Diphtheria  Is  Spread.  —  It  has  been  said  that  the 
milder  the  case  of  diphtheria  is,  the  more  danger  it  offers 
to  everybody  except  the  patient.  That  is  because  a 
mild  case  is  less  likely  to  be  regarded  as  serious  and 
fewer  precautions  are  apt  to  be  taken.  In  fact,  the  body 
is  so  well  able,  in  some  cases,  to  neutralize  the  disease  that 
the  patient  may  think  he  has  only  a  cold,  and  take  no 
precautions  at  all  against  infecting  others.  Yet  the 
germs  from  such  a  very  mild  case  may  be  carried  to 
other  people  and  produce  in  them  the  most  serious  form 
of  the  disease,  because  they  are  not  good  antitoxin  makers. 

When  the  disease  is  recognized,  the  patient  should  be 
isolated,  either  at  home  or  in  a  hospital,  and  no  one 
should  see  him  except  the  doctor  and  the  nurses.  He 
must  be  kept  away  from  others  as  long  as  the  dangerous 
germs  are  still  alive  in  his  throat,  which  is  usually  two 
or  three  weeks  after  his  recovery.  The  germs  adhere  so 
loosely  to  the  walls  of  the  throat  that  they  are  easily 
detached.  They  get  into  the  saliva,  and  will  be  sure  to 
be  left  upon  anything  that  the  patient  may  have  in  his 
mouth :  his  fingers,  pencils,  drinking  cup,  knife,  fork, 
spoon,  etc.  Another  person  using  the  same  pencil  or 
drinking  cup  may  get  the  germs  in  his  mouth,  and  so 
may  "  catch "  the  disease.  Thus  these  germs  may  be 
carried  from  person  to  person  in  a  family  or  in  a  school, 
especially  as  they  remain  alive  for  several  days  after 
leaving  the  mouth.  Diphtheria  patients  should  use,  so 
far  as  possible,  articles  that  may  be  rendered  safe  and 
free  from  germs  by  boiling  for  ten  minutes. 

Precautions  against  Diphtheria.  —  It  is  a  wise  rule  never 
to  put  into  the  mouth  anything  that  another  has  had  in 


170  PHYSIOLOGY   AND   HEALTH 

his  mouth,  and  to  keep  away  from  persons  who  have 
sore  throats.  Sometimes  a  person  who  is  perfectly  well 
has  the  germs  in  his  throat,  and  although  they  are  not 
injuring  him  because  he  is  for  some  reason  immune  against 
the  disease,  he  might  be  the  means  of  giving  this  dreaded 
disease  to  his  schoolmates.  For  this  reason  the  school 
nurse  or  doctor  occasionally  makes  an  examination  of  the 
throats  of  all  the  children  in  a  school  to  see  whether  any 
one  of  the  well  children  has  the  germs  in  his  throat. 
Such  a  person  would  be  called  a  bacillus  carrier.  If 
there  are  any  such  carriers  found,  they  are  kept  out  of 
school  for  a  few  days,  until  it  can  be  shown  that  the 
dangerous  germs  have  disappeared  from  their  throats. 
Sometimes  a  pupil's  parents  fail'  to  understand  why 
he  has  been  sent  home  from  school  by  the  health  officer 
when  he  is  not  ill;  the  reason  is  because  he  may  be  a 
source  of  danger  to  his  companions. 

Colds.  —  The  more  or  less  slight  indisposition  that  is 
called  a  "  cold  "  is  badly  named ;  it  leads  many  to  think 
that  colds  come  from  being  cold,  from  staying  out  in  the 
cold.  The  fact  is  that  if  the  name  were  used  only  for 
trouble  so  caused  most  of  us  would  never  have  a  single 
"  cold  "  as  long  as  we  lived.  A  cold  is  really  an  in- 
flammation of  the  nose,  throat,  windpipe,  or  lungs.  In- 
flammation means  an  enlargement  of  the  blood  vessels, 
and  when  that  occurs  in  the  air  passages  their  linings 
become  very  sensitive.  Usually  a  large  amount  of 
liquid  is  secreted  and  runs  out  from  the  nostrils  or  down 
into  the  throat.  If  the  inflammation  is  only  in  the  nose 
and  throat,  we  call  it  a  "  cold  in  the  head  "  ;  if  it  extends 
further  down,  into  the  bronchi  or  the  lungs,  it  is  called 


SOME  OF  THE  NATION'S  UNSEEN  FOES  171 

bronchitis.  If  a  cold  gets  down  into  the  lungs,  it  is  best 
to  have  the  advice  of  a  physician  to  prevent  more  serious 
trouble. 

A  cold  in  the  head  is  uncomfortable  but  in  itself  it  is 
commonly  of  no  great  importance,  for  it  will  disappear 
in  a  few  days.  It  may,  nevertheless,  do  much  harm  by 
producing  just  the  conditions  that  are  favorable  for  the 
germs  that  cause  bronchitis  or  pneumonia. 

The  cause  of  a  cold  is  probably  the  multiplying  of 
some  of  the  germs  that  are  usually  in  the  mouth  and 
nose  waiting  a  chance  to  grow.  Why  is  it,  if  they  are 
always  there,  that  they  cause  a  cold  at  one  time  and  not 
at  another?  One  of  the  ways  in  which  we  help  them  is 
by  living  in  warm  rooms  and  bundling  up  our  necks  and 
faces  when  we  go  out  on  a  cold  day.  People  who  live 
out  of  doors,  like  soldiers  and  sailors,  do  not  have  colds, 
these  troubles  being  confined  almost  entirely  to  those 
who  live  indoors.  Living  in  warm  rooms  and  wrapping 
oneself  too  warmly  tends  to  weaken  the  throat  until  it 
cannot  endure  cold  air. 

The  way  to  avoid  colds  is  to  live  as  much  as  possible 
in  the  open ;  to  sleep  with  windows  open  even  in  winter ; 
to  take  cold  baths;  and  to  avoid  overcrowded  rooms, 
like  cheap  moving-picture  shows.  One  person  may 
catch  a  cold  from  another,  and  it  is  best  therefore  not  to 
stay  close  by  a  person  who  has  a  cold.  If  those  who 
have  colds  were  thoroughly  considerate,  they  would 
neither  cough  nor  breathe  in  the  faces  of  others,  and 
would  see  that  boiling  water  is  poured  on  their  hand- 
kerchiefs before  sending  them  to  be  washed.  They 
would  never  dry  a  handkerchief  in  the  air  or  on  a  radiator, 


172  PHYSIOLOGY   AND    HEALTH 

without  washing,  for  that  is  very  liable  to  spread  the 
germs. 

The  Grip  or  Influenza.  —  The  grip  is  much  more 
serious  than  a  cold,  which  it  often  resembles  at  the  start ; 
sometimes  the  effects  of  it  last  for  weeks.  The  grip  is 
certainly  contagious,  and  the  germs  that  cause  it  are 
sure  to  be  in  the  sputum  (matter  coughed  up)  and  in 
the  discharges  from  the  nose  of  the  patient.  The  same 
precautions  should  therefore  be  taken  as  with  the  sputum 
of  consumptives.  Where  possible  the  patient  should  be 
isolated  from  others,  especially  from  elderly  people 
who  are  most  likely  to  take  the  disease  and  with  whom 
it  is  most  dangerous.  The  grip  prepares  the  way  for 
pneumonia  by  decreasing  a  person's  resistance  to  the 
pneumonia  germ.  We  know  of  no  means  of  preventing 
it,  except  to  avoid  being  with  those  who  are  ill  with  the 
disease  and  to  keep  up  the  general  health. 

Pneumonia.  —  It  has  long  been  supposed  that 
pneumonia,  which  is  a  very  serious  disease  of  the  lungs, 
came  from  a  "  bad  cold."  Old  people  used  to  say, 
"  If  you  do  not  take  care  of  that  cold  you  will  have 
pneumonia."  That  seemed  foolish  when  it  was  dis- 
covered that  pneumonia  is  caused  by  a  germ.  But 
there  was  good  sense,  after  all,  in  the  old  people's  saying, 
for  the  pneumonia  germs  are  widely  distributed;  we 
are  continually  encountering  them,  and  they  are  often 
found  in  the  mouths  of  well  people,  doing  them  no 
injury  at  all  when  their  lungs  are  sound.  If  the  lungs 
become  inflamed  by  a  • "  cold  on  the  lungs,"  the  pneu- 
monia germs  may  then  get  a  chance  to  enter  at  the 
inflamed  places,  thus  causing  the  disease.  For  this 


SOME  OF  THE  NATION'S  UNSEEN  FOES 


173 


reason  a  cold  in  the  chest  should  be  given  particular 
attention. 

Though  it  is  slightly  contagious,  there  is  little  danger 
of  taking  pneumonia  if  people  are  not  allowed  to  come 
into  too  close  contact  with  the  patient,  especially  if 
the  sputum  is  burned  or  disinfected.  The  need  of  fresh 
air  is  greater  in  pneumonia  than  in  any  other  disease. 
Sometimes  pneumonia  patients  are  treated  in  the  open 
air  or  given  pure  oxygen  to  breathe. 

Tuberculosis  —  The  Worst  Foe 

The  Tubercle  Bacillus.  —  There  is  a  slender  disease 
germ,  called  tubercle  bacillus,  that  causes  more  deaths 
in  our  country  than  anything  else  (see  Figure  51).  If 


RESPIRATORY 


DIGESTIVE 


A  B  C  D  F  G  H 

FIG.  51.  —  COMPARATIVE  NUMBERS  OF  DEATHS  FROM  VARIOUS  DISEASES. 

The  numbers  of  deaths  from  the  diseases  mentioned  are  proportional  to  the 
height  of  the  figures.  A,  tuberculosis;  B,  pneumonia;  C,  typhoid  fever; 
D,  other  intestinal  diseases;  F,  heart  diseases;  G,  accidents  of  all  kinds; 
H,  old  age. 


174  PHYSIOLOGY   AND   HEALTH 

we  could  kill  these  germs,  we  could  get  rid  of  the  disease 
they  produce.  They  grow  only  in  the  bodies  of  men 
and  a  few  animals,  and  they  cannot  live  more  than  a 
year  or  two  outside  the  body.  Hence,  if  every  one  who 
has  the  disease  to-day  could  make  certain  that  he  did 
not  let  any  of  the  germs  escape  to  injure  others,  there 
would  be  no  more  new  cases  except  those  started  from 
the  germs  already  spread  abroad,  and  those  could  not 
be  dangerous  for  more  than  two  years.  So  after  two 
years  there  would  be  no  new  cases  at  all,  and  this  would 
mean  that  in  our  country  alone  175,000  deaths  from  the 
disease  would  be  saved  every  year,  and  more  than 
$300,000,000. 

What  Tuberculosis  Is.  —  The  disease  caused  by  the 
tubercle  bacillus  is  called  tuberculosis.  The  bacillus  may 
grow  in  practically  any  part  of  the  body.  Among 
children,  it  may  attack  the  hip  bone,  causing  hip  disease ; 
in  the  lymphatic  glands,  it  used  to  be  called  scrofula; 
in  the  lungs,  it  is  called  tuberculosis  of  the  lungs,  or 
consumption  —  and  this  is  the  form  in  which  it  is  most 
common.  Physicians  now  know  (1)  how  tuberculosis 
is  acquired  ;  (2)  how  it  may  be  prevented  ;  (3)  how  most 
forms  of  it  may  be  cured.  Yet  with  all  this  knowledge 
they  cannot  begin  to  fight  the  disease  as  they  might, 
because  many  people  will  not  believe  that  this  unseen 
enemy  is  really  dangerous  until  it  attacks  some  one  of 
their  own  circle.  If  we  could  see  every  living  tubercle 
bacillus  around  us  as  a  tiny  soldier  with  a  gun,  we  should 
probably  be  much  frightened  by  their  number,  and  much 
encouraged,  at  the  same  time,  to  see  how  readily  they 
can  be  slain. 


SOME  OF  THE  NATION'S  UNSEEN  FOES  175 

How  Tuberculosis  Is  Acquired.  —  There  is  only  one 
way  in  which  tuberculosis  is  ever  acquired  —  through 
taking  into  the  body  from  the  outside  the  bacillus  that 
produces  the  disease. 

Not  Inherited.  —  It  used  to  be  thought,  before  the 
bacillus  was  discovered,  that  certain  families  were 
"  fated  "  to  die  of  tuberculosis.  If  the  parents  had  it, 
the  children  were  expected  to  have  it;  they  were  sup- 
posed to  inherit  it  from  the  parents,  just  as  they  in- 
herited eyes  of  a  certain  color.  Now  it  is  known  that 
this  is  not  the  case ;  the  germ  cannot  pass  in  this  way 
from  parents  to  children.  Children  do  not  "  inherit  " 
bad  grammar,  they  pick  it  up  from  the  conversation 
that  they  hear  day  by  day.  In  the  same  way  children 
may  take  tuberculosis  from  some  member  of  the  family, 
or  they  may  be  guarded  against  the  bacillus  so  that  they 
need  never  have  the  disease. 

Germs  Ever  Present.  —  In  parts  of  the  world  where  men 
do  not  live,  the  bacillus  is  not  found,  but  wherever 
men  live  it  exists  in  large  numbers.  It  goes  floating 
about  in  the  air  we  breathe,  alive  but  not  active.  The 
germ  is  a  hardy  one,  for  cold  does  not  harm  it,  and  it 
may  survive  much  heat,  though  a  moment's  boiling  will 
kill  it.  To  produce  the  disease  the  germ  must  usually 
find  entrance  by  the  mouth  or  nose.  When  it  can  get  a 
chance  to  grow  it  multiplies  rapidly,  by  the  simple 
method  of  growing  and  then  dividing,  and  it  is  one  of 
the  most  difficult  foes  that  the  body  has  to  fight.  When 
the  body  disposes  of  bacilli  in  the  lungs,  there  is  left,  at  the 
spot  where  the  conflict  took  place,  a  sign  of  it  which  the 
doctors  call  a  scar.  Such  scars  have  been  found  in  the 


176  PHYSIOLOGY  AND   HEALTH 

lungs  of  many  people  who  never  had  the  disease  and 
never  even  knew  that  they  were  threatened  with  it ;  but 
the  scar  tells  the  story,  and  shows  that  the  body  at  one 
time  fought  and  overcame  the  invading  foe. 

Germs  in  Dust.  —  Outside  the  body  the  bacillus  can 
last  longest  in  damp,  filthy  places.  Sunshine  and  fresh 
air  are  its  foes,  but  it  is  well  pleased  with  a  dust  heap; 
there  the  masses  of  germs  may  be  gradually  reduced  to  a 
powder,  and  then  every  gust  of  wind  that  blows  over  the 
heap  of  dirt  may  carry  them  into  the  air  which  the  pas- 
serby has  to  breathe.  We  can  take  many  precautions  in 
regard  to  our  food,  since  we  can  choose  what  we  eat  and 
how  it  shall  be  prepared;  but  we  cannot  filter  the  air 
we  breathe,  or  put  it  through  any  other  process  that 
shall  remove  the  germs. 

Fortunately  for  us,  after  the  germs  have  become  dry 
and  have  been  out  doors  in  the  sun  for  a  while  they 
become  harmless.  Yet  there  are  about  10,000,000 
people  in  this  country  to-day  who  will  finally  die  of 
this  disease  unless  our  fight  against  it  becomes  more 
vigorous  than  it  has  been.  The  sad  thing  about  it  is 
that  nearly  every  one  of  these  deaths  could  be  prevented 
if  people  would  only  use  proper  precautions. 

How  Consumptives  Spread  the  Disease.  —  If  the  dis- 
ease is  in  the  lungs,  the  patient  is  constantly  coughing  up 
matter  which  contains  large  numbers  of  the  bacilli.  These 
can  be  made  harmless  by  proper  care,  but  if  the  sputum, 
laden  with  deadly  germs,  is  allowed  to  soil  the  hands  or 
clothes  of  the  patient,  or  if  it  is  allowed  to  dry  upon 
articles  used  by  him,  or  on  the  floor,  so  becoming  powdered 
and  mingled  with  the  dust,  any  one  who  comes  into  the 


SOME   OF  THE  NATION'S  UNSEEN  FOES  177 

room  may  breathe  in  the  germs  or  may  get  them  on  his 
hands  and  so  into  his  mouth.  The  room  of  a  careless 
consumptive  is  thus  a  danger  spot. 

On  the  other  hand,  the  consumptive  is  not  a  source  of 
danger  if  he  is  careful  in  his  habits.  His  breath  does 
not  contain  the  germs,  though  when  he  coughs  or  sneezes 
tiny  drops  of  sputum  which  are  laden  with  germs  may 
be  blown  out  of  his  mouth.  If  he  holds  a  handkerchief 
before  his  mouth  when  he  coughs  or  sneezes,  these  will 
be  caught  in  the  handkerchief;  but  if  he  coughs  them 
into  the  air,  they  will  float  around  for  some  distance  and 
be  a  danger  to  people  about  him.  To  shun  a  careful 
consumptive  who  faithfully  follows  the  precautions  given 
on  page  182  would  be  as  foolish  as  to  refuse  to  ride  in 
a  carefully  inspected  elevator  because  you  know  that 
badly  constructed  elevators  sometimes  break  down  and 
kill  their  passengers.  There  is  probably  no  place  in 
which  there  is  so  little  danger  of  acquiring  consumption 
as  in  a  sanitarium  where  consumptive  patients  are  cared 
for,  since  all  the  many  patients  there  know  how  to  guard 
their  sputum ;  while  one  of  the  most  dangerous  places 
is  the  room  of  a  consumptive  who  pays  no  attention  to 
the  matter. 

How  Tuberculosis  May  Be  Prevented.  —  Evidently 
the  only  way  to  stamp  out  tuberculosis  is  to  kill  all  the 
bacteria  that  cause  it.  Whether  this  will  ever  be  done 
we  cannot  say,  but  it  will  surely  take  years.  Meantime, 
there  are  several  things  that  every  one  ought  to  do  to 
guard  himself  against  acquiring  the  disease. 

1.  Guarding  against  the  Bacilli.  —  It  is  not  wise  to  go 
among  careless  consumptives  unless  duty  takes  us  there, 


178  PHYSIOLOGY   AND   HEALTH 

and  then  we  have  the  right  to  try  to  persuade  them  to 
take  proper  precautions.  Nor  is  it  wise  to  go  habitually 
to  places  where  people  spit  on  the  floors  or  walls.  It  is 
better  to  stay  away,  even  if  there  is  no  o"ne  present  whom 
you  know  to  be  a  consumptive.  Some  rooms  occupied 
by  careless  consumptives  become  so  badly  infected  with 
the  germs  that  any  one  who  goes  to  live  in  them  is  ex- 
posed to  constant  danger. 

Those  who  move  into  a  house  or  apartment  that  has 
been  occupied  by  others  ought  to  make  inquiries  about 
the  previous  tenants.  If  they  cannot  get  satisfactory 
information,  then  the  safe  thing  is  to  make  all  the  rooms 
sanitary,  since  the  tubercle  bacillus  may  live  a  couple 
of  years  in  dark,  damp  places,  or  in  undisturbed  cor- 
ners. So  all  the  walls  should  be  cleaned,  repapered 
if  possible,  or  carefully  scrubbed  with  a  dry  mop  if  new 
paper  cannot  be  had ;  the  woodwork  should  be  repainted 
or  thoroughly  scoured ;  the  floors  and  every  nook  and 
cranny  that  may  contain  dust  should  be  scrubbed  with 
a  chloride  of  lime  mixture  (one  part  lime  and  twelve 
parts  water).  Then,  with  a  safe,  clean  house  in  which 
to  live,  the  family  should  observe  in  sweeping  and  dust- 
ing the  precautions  already  suggested  against  raising  the 
dust  that  is  continually  entering  our  rooms. 

2.  The  Power  to  Resist  the  Bacilli.  —  If  our  bodies  are 
kept  in  good  condition  they  have  great  power  of  resisting 
the  attacks  of  the  bacilli,  which  do  not  thrive  in  vigorous, 
healthy  tissue.  The  athlete  guards  himself  against  all 
sorts  of  minor  ailments,  like  colds  and  indigestion,  be- 
cause he  wants  to  be  in  the  best  possible  condition  for 
the  contest  before  him.  If  each  one  of  us  in  his  own 


SOME   OF  THE   NATION'S  UNSEEN   FOES  179 

way  were  to  use  equal  care  about  keeping  himself  con- 
stantly in  condition  to  resist  the  body's  foes,  we  should 
not  have  much  occasion  to  fear  their  attacks ;  this  again 
means  observing  the  rules  of  health  already  given,  and 
avoiding  the  use  of  alcohol.  There  is  also  one  particular 
thing  we  can  do  to  keep  the  lungs  themselves  in  good 
condition.  By  increasing  the  lung  capacity  and  keeping 
all  parts  of  the  lungs  active,  as  has  been  suggested,  we 
do  much  to  guard  against  their  becoming  the  lodging 
place  for  the  bacilli. 

The  Cure  of  Consumption.  —  Fortunately  consumption 
can  be  cured,  but  curing  it  is  like  stopping  a  leak  in  a 
dike  —  the  earlier  you  start,  the  better  chance  you 
have.  Many  people  waste  precious  months  trying  to 
deceive  themselves  into  believing  that  they  "  have  a 
bad  cold  "  or  "  a  bad  throat,"  instead  of  meeting  the 
situation  squarely  and  starting  the  fight  when  all  the 
chances  are  in  their  favor.  Every  one  who  has  a  per- 
sistent cough  ought  to  consult  his  doctor  as  to  the  cause 
of  it,  and  the  cure. 

Consumption  is  not  cured  by  taking  medicine.  None 
of  the  many  remedies  that  are  advertised  as  "  cures  " 
should  be  taken.  Most  of  them  contain  alcohol  in  some 
form,  and  alcohol  is  almost  certain  to  make  the  disease 
worse.  Remember,  nothing  that  can  be  put  into  a 
bottle  will  stop  the  work  of  the  bacillus  and  make  the 
consumptive  well  again. 

Patients  frequently  go  away  from  home  into  a  differ- 
ent climate ;  but  a  change  of  climate  is  not  the  first 
requisite  for  a  cure.  Before  doctors  knew  how  to  cure 
the  disease,  change  of  climate  was  usually  advised ;  now 


180 


PHYSIOLOGY   AND   HEALTH 


it  is  considered  desirable  only  when  the  patient  can  easily 
afford  to  remain  idle  for  some  length  of  time  and  can  also 
afford  to  meet  the  heavy  expense  of  life  away  from  home. 
Change  of  climate  is  much  less  important  than  air, 
6im,  food,  and  rest;  those  are  tho  only  known  cures  for 
consumption.  The  principle  on  which  they  work  is  to 

reenf  orce  the  body 
in  its  attempts  to 
resist  the  disease. 
Fresh  Air  and 
Sunlight.  —  Night 
and  day,  summer 
and  winter,  the 
patient  needs  all 
the  fresh  air  possi- 
ble, and  he  does 
not  need  to  have 
out-of-doors  made 
over  for  him.  Or- 
dinary winds  and 
currents  of  air  are  not  injurious  to  him,  for  he  must  be 
so  warmly  clothed  as  to  protect  himself  against  being 
chilly.  He  will  be  amazed  to  find  that  cold  air  is  good 
for  his  sick  lungs.  One  of  the  advantages  of  open-air 
sanatoria  is  that  the  patients  learn  from  each  other  how 
to  live  out  of  doors  and  to  consider  .cold  air  their  best 
friend. 

The  consumptive  is  fortunate  if  he  can  stay  at  home 
and  live  in  a  well-ventilated  tent  or  on  a  veranda  (see 
Figure  49)  that  can  be  curtained  to  protect  him  from 
driving  storms.  He  should  sleep  out  of  doors,  and  if  he 


FIG.  52.  —  A   SUN  PARLOR  DESIGNED  FOB 
TUBERCULOSIS  PATIENTS. 


SOME   OF  THE  NATION'S   UNSEEN   FOES  181 

is  not  at  work  should  count  as  lost  every  moment  spent 
indoors,  away  from  the  sunshine  which  is  an  important 
part  of  his  cure.  One  will  save  on  doctor's  bills  what 
he  spends  on  sleeping  porches.  Keep  the  windows  open 
and  the  pill  box  stays  shut.  If  the  air  and  sunshine 
could  penetrate  into  the  diseased  tissues  they  would  soon 
kill  the  germs  ;  as  they  cannot,  the  best  thing  is  to  get  all 
possible  benefit  from  them.  When  cases  of  tuberculosis 
are  taken  in  time,  the  patient  can  usually  be  cured  in  his 
own  home. 

Tissue-building  Food.  -  -  The  tubercle  bacilli  destroy 
the  tissues  of  the  body.  But  if  the  tissues  can  be  built 
up  faster  than  the  bacilli  break  them  down,  the  patient 
will  recover.  So  he  must  have  as  much  food  of  the  right 
kind  as  his  body  can  take  care  of.  He  needs  milk  and 
eggs  in  as  large  quantities  as  he  can  digest  them;  they 
should  come  between  his  meals  (he  is  an  exception  to  the 
rule  in  this  respect)  and  should  not  prevent  his  eating 
three  regular  meals,  consisting  of  meat  and  any  other 
forms  of  protein  that  he  can  digest,  vegetables,  and  fruit. 
It  is  not  wise  for  him  to  eat  more  of  the  fuel  foods  than 
may  be  needed  to  keep  the  body  warm  and  to  give 
the  needed  energy.  Being  in  the  open  air  will  help  him 
to  relish  extra  food. 

Rest  and  Exercise.  —  In  cases  of  consumption  that  are 
taken  in  hand  at  the  start,  the  patient  may  be  able  to 
do  his  regular  work,  with  safety  to  himself  and  to  others. 
When  cases  have  progressed  further,  it  is  of  prime  im- 
portance that*  the  patient  should  have  much  rest,  keep- 
ing quiet  most  of  the  day,  doing  absolutely  nothing,  so 
that  all  his  force  may  be  spent  in  combating  the  disease. 


182  PHYSIOLOGY   AND   HEALTH 

If  he  can  take  a  little  light  exercise  without  tiring  him 
or  greatly  increasing  his  rate  of  breathing,  that  will  be 
useful,  but  it  should  be  carefully  watched,  and  decreased 
or  increased  as  his  progress  warrants.  The  exercise 
should,  however,  be  only  a  break  in  the  periods  of  rest. 
The  Consumptive  Can  Protect  Others.  —  Every  careful 
consumptive  should  be  honored  as  a  public-spirited 
citizen ;  the  nation  owes  him  its  thanks  if  he  is  faithful 
in  guarding  those  about  him  from  the  disease.  In  addi- 
tion to  the  following  general  suggestions  every  con- 
sumptive ought  to  have  simple  directions  about  various 
details  of  his  life.  The  Charity  Organization  Society  of 
New  York  City  issues  an  excellent  circular  which  it 
sends  free  on  request. 

1.  The  consumptive's  first  care  must  be  the  destruction 
of  the  disease-laden  sputum.     It  should  never  be  swal- 
lowed, but  should  either  be  coughed  into  paper  napkins 
which  can  be  burned,  or  into  cups  containing  a  weak 
solution  of  carbolic  acid  (five  teaspoonfuls  to  a  pint  of 
water) ;    the  paper  cups  are  best  because  they  can  be 
burned  with  their  contents. 

2.  The  hands  and  mouth  should  be  washed. frequently 
in  warm  water  and  soap. 

3.  In  coughing  or  sneezing,  care  should  be  taken  to 
cover  the  mouth  and  nose  with  a  paper  napkin,  so  that 
none  of  the  spray  which  carries  germs  may  get  into  the 
air.     The    napkin    should    be    promptly    burned.     If    a 
paper  napkin  is  not  at  hand,  a  handkerchief  or  piece  of 
cloth  may  be  used,  but  this  should  afterwards  be  placed 
in  boiling  water  for  a  few  moments,  if  it  is  too  valuable 
to  burn. 


SOME   OF  THE   NATION'S  UNSEEN  FOES  183 

4.  The  consumptive  should  sleep  alone,  and  both  his 
body  clothes  and  his  bed  linen  should  be  washed  sepa- 
rately from  other  clothes ;  they  should  not  be  allowed 
to  stand  around,  but  should  be  placed  in  water  until 
ready  for  washing. 

Alcohol  and  Tuberculosis.  —  Statistics  show  that  there 
is  a  larger  proportion  of  tuberculosis  cases  among  those 
who  take  alcoholic  drinks  than  among  non-drinkers. 
Alcohol  not  only  makes  conditions  favorable  to  the 
bacillus  but  it  is  harmful  in  the  cure  of  consumption. 
The  great  need  is  to  have  the  digestion  in  the  best  possible 
condition,  and  the  lungs  actively  engaged  in  the  purify- 
ing of  the  blood,  so  that  the  patient  may  take  as  much 
nourishment  as  possible  in  order  to  build  up  the  tissues 
and  to  counteract  the  power  of  the  bacteria.  Both  the 
stomach  and  lungs  are  unfavorably  affected  by  the  use  of 
alcohol. 

Tobacco,  also,  is  bad  for  consumptives,  and  for  those 
predisposed  to  the  disease,  as  it  tends  to  weaken  the 
heart  and  thus  to  obstruct  the  circulation,  making  it 
more  difficult  for  the  lungs  to  resist  attack. 

Animal  Tuberculosis.  —  When  it  was  discovered  that 
other  animals  beside  man  are  subject  to  tub.erculosis, 
it  was  greatly  feared  that  human  beings  might  be  acquir- 
ing the  disease  from  them,  especially  from  the  meat  and 
the  milk  of  diseased  cattle.  Long  and  extensive  study 
has  proved  that  there  is  no  danger  from  cooked  meat  or 
pasteurized  milk.  Ordinary  market  milk  cannot  safely 
be  given  raw  to  babies  and  children,  for  it  has  been 
demonstrated  that  raw  milk  from  tuberculous  cows  may 
produce  tuberculosis  among  children.  Since  there  are 


184  PHYSIOLOGY  AND   HEALTH 

now  many  cows  which  have  this  disease,  and  since  their 
milk  is  likely  to  be  a  part  of  the  supply  furnished  to  any 
city,  it  is  not  safe  to  give  the  ordinary  market  milk  to 
children  unless  we  can  be  sure  that  it  has  been  properly 
pasteurized. 

Some  Results  of  the  Struggle.  —  Communities  have 
been  carrying  on  a  determined  warfare  against  this 
disease  since  1875,  or  thereabouts,  and  the  results  of 
this  combat  have  been  surprisingly  happy.  In  1865 
the  deaths  from  this  disease  were  about  40  per  year  for 
each  10,000  people ;  fifty  years  later  the  mortality  had 
dropped  in  some,  places  to  15  per  10,000,  in  others 
to  20.  This  means  that  in  1865  one-quarter  of  the 
deaths  were  caused  by  tuberculosis,  while  now  less  than 
one-seventh  of  them  are  so  caused.  Although  about 
175,000  people  still  die  of  it  each  year  in  the  United 
States,  more  than  300,000  would  die  each  year  were  it 
not  for  the  precautions  that  are  now  being  taken;  that 
is,  there  are  at  least  150,000  people  in  our  country  who 
would  have  died  of  tuberculosis  during  the  last  twelve 
months,  had  we  not  adopted  methods  of  checking  the 
spread  of  the  disease.  It  means  that  the  fight  against 
it  is  saving  the  life  of  one  person  every  three  minutes, 

day  and  night. 

QUESTIONS 

1.  Why  are  germs  more  dangerous  than  wild  animals? 

2.  What   conditions  of  modern  life  tend  to  make  certain  germ 
diseases  a  greater  menace  than  they  were  a  century  or  two  ago? 

3.  What  precautions  should  one  take  to  avoid  contracting  such 
diseases  as  mumps,  whooping  cough,  or  tonsillitis?    Have  you  ever 
heard  of  serious  consequences  resulting  from  one  of  these  diseases? 

4.  Find  out  how  antitoxin  is  prepared. 


SOME   OF  THE  NATION'S  UNSEEN  FOES  185 

5.  The  Board  of  Health  of  a  certain  city  in  which  there  was  a 
severe  epidemic  of  grip  issued  warnings  cautioning  people  to  avoid 
crowded  halls  and  theaters  and  crowded  street  cars,  not  to  use  public 
telephones,  and  to  get  plenty  of  sleep.     Was  this  good  advice?     Why 
do  you  think  so  ? 

6.  Why  should  one  never  drink  from  a  cup  that  another  has  used 
until  it  has  been  sterilized  in  some  way,  even  though  the  person  using 
it  was  apparently  perfectly  clean  and  healthy? 

7.  Is  a  Maine  lumberman  likely  to  have  frequent  colds?     How 
about  a  clerk  in  a  store?     What  can  the  clerk  do  to  avoid  them? 

8.  Why  is  it  unwise  to  neglect  a  severe  cold? 

9.  What  are  some  of  the  forms  which  tuberculosis  takes?    Which 
is  the  most  common?     How  is  tuberculosis  acquired? 

10.  If  tuberculosis  is  never  inherited,  how  do  you  account  for  the 
fact  that  children  of  a  tubercular  parent  often  are  very  likely  to  have 
the  disease? 

11.  Does  your  city  have  a  law  against  spitting  in  public  places? 
Do  you  think  it  is  important  to  have  such  a  law?     Do  you  consider 
that  it  is  well  enforced  ? 

12.  What  precautions  should  a  tubercular  patient  take  in  order 
not  to  be  a  danger  to  others  ? 

13.  Is  there  any  medicine  that  will  cure  consumption?    What  is 
the  only  treatment  to  which  it  will  respond  ? 

14.  Can  you  give  any  reason  why  persons  living  in  dark,  damp 
rooms  are  more  likely  to  have  consumption  than  those  living  in  sunny 
ones? 

15.  Write  a  theme  on  ways  and  means  of  stamping  out  tuberculosis 
in  your  community. 


CHAPTER  VII 

HOW  THE  BODY   IS   MADE   MOVABLE 
How  the  Muscles  Work 

The  Need  for  Motion.  —  Plants  use  most  of  their  food 
for  growth;  animals  use  most  of  their  food  for  motion 
and  a  comparatively  small  amount  for  growth.  There 
are  some  parts  of  the  body,  like  the  upper  jaw,  that  are 
not  made  to  move,  but  in  most  parts  motion  is  possible. 
Traveling  from  one  place  to  another,  holding  and  carry- 
ing things,  eating  and  talking,  are  all  dependent  upon 
motion.  It  is  by  slight  changes  of  "  expression/7  made 
by  motions  of  different  parts  of  the  face,  that  one  can 
tell  whether  a  friend  is  gay  or  unhappy,  pleased  or  dis- 
pleased. Motion  of  all  kinds  is  made  possible  by  the 
muscles. 

How  Motion  Is  Produced.  —  Motion  in  the  body  is 
always  produced  by  muscles ;  at  the  same  time  they 
could  not  give  motion  without  the  combined  aid  of  the 
bones  and  the  nervous  system.  No  matter  how  strong  a 
man's  muscles  may  be,  without  bones  he  could  not  even 
sit  in  a  chair;  however  powerful  his  arm  muscles,  he 
could  not  even  lift  a  pin  if  the  muscles  had  no  hand  bones 
to  pull  against. 

A  muscle  will  not  pull  a  bone  without  receiving  orders 
to  do  so  ;  it  gets  its  orders  from  the  nervous  system.  In 

186 


HOW  THE  BODY  IS  MADE  MOVABLE  187 

this  section  we  shall  consider  the  part  played  by  the 
muscles  and  the  bones  without  making  reference  to  what 
is  done  by  the  nervous  system ;  but  the  pupil  should 
always  keep  in  mind  the  fact  that  no  muscle  acts  of  itself. 
Every  muscular  action  is  started  at  the  direction  of  some 
part  of  the  nervous  system. 

The  Action  of  Muscles  and  Tendons.  —  A  grown  man 
ought  to  weigh  from  two  to  two  and  one-half  pounds 
for  every  inch  of  height.  His  muscles  constitute  about 
half  his  weight ;  they  form  what  is  called  the  "  flesh  " 
(not  the  fat)  of  the  body.  We  seldom  see  the  shapes  of 


FIG.  53.  —  THE  BICEPS  MUSCLE  AND  ITS  ATTACHMENTS. 
Showing  the  method  of  moving  the  arm,  the  dotted  line  indicat- 
ing the  position  when  the  biceps  contracts. 

the  muscles  because  they  are  overlaid  with  fat  and  skin, 
One  of  the  easiest  to  observe  is  the  biceps  muscle  of  the 


188 


PHYSIOLOGY   AND    HEALTH 


arm.  Test  it  by  placing  the  right  hand  on  the  biceps  of 
the  left  arm.  When  you  move  the  left  forearm  up  and 
down  you  can  feel  that  the  biceps  muscle  is  largest  in 
the  middle.  Figure  53  shows  how  the  ends  of  that  muscle 
taper,  and  that  those  ends  are  attached  to  the  bones  by 
firm  white  bands,  called  tendons. 

A  tendon  is  not  made  of  muscle ;  it 
does  not  expand  and  contract  as  all 
muscles  do,  and  it  cannot  be  stretched. 
The  function  of  the  tendons  is  to  trans- 
mit the  pull  of  the  muscle  to  the  bone 
which  the  muscle  moves,  just  as  the  tugs 
of  a  harness  transmit  the  horse's  pull 
to  the  wagon.  The  tendons  are  of  dif- 
ferent lengths  ;  some  are  very  short,  some 
are  long  like  those  which  extend  from  the 
arm  to  the  fingers  and  from  the  leg  to 
the  toes. 

Figure  54  shows  the  arrangement  of 
the  muscles  and  tendons  of  the  left  hand 
and  arm.     Muscles  are  not  necessarily 
near  the  bone  they  move,  as  you  can 
see  by  feeling  how  they  work  in  your  own 
arm.     With  the  right  hand  grasp  the 
A.I.,  the  annular  liga-   left    arm   just   below   the   elbow,   then 
ment,  holding  the   clench  the  fingers  of  the  left  hand  and 

tendons  in  position.  ,,  ..  ,.  ,-,       ~ 

open  them ;  the  motion  of  the  fingers  is 
produced  by  muscles  in  the  arm,  and  you  can  see  how 
tightly  the  tendons  stretch  on  the  inside  of  the  wrist  as 
the  fist  is  clenched.  If  the  muscles  that  move  the  fingers 
did  not  have  those  long  tendons  but  had  to  extend  down 


HOW  THE  BODY  IS  MADE  MOVABLE 


189 


through   the  wrist  to  the  fingers,  how  unshapely  they 
would  make  the  wrist  and  the  hands. 

See  what  a  long  pull  there  is  on  those  finger  tendons. 
One  end  of  the  tendon  is 
attached  to  a  finger  bone  and 
the  other  end  to  a  muscle 
up  in  the  arm.  When  the 
muscles  contract,  the  long 
tendons  might  bulge  out  near 
the  wrist,  if  it  were  not  for 
the  firm  band  that  goes 
around  them  and  straps 
them  down  just  enough  to 
keep  them  in  place  and  not 
enough  to  interfere  with  their 
working  easily.  That  band 
shows  in  Figure  54.  There 
are  similar  bands  serving  the 
same  purpose  in  other  parts 
of  the  body. 

Muscles  Differently  Con- 
trolled.—  While  the  motion 
of  all  muscles  is  directed  by 
the  brain,  the  directions  are 
given  in  two  different  ways ; 
and  the  muscles  are  classified 
according  to  the  way  in  which 
they  receive  their  directions. 
(1)  The  voluntary  muscles 

are  under  the  control  of  the  will ;  the  brain  gives  them 
orders  when  we  wish  them  to  move.     The  muscles  of  the 


FIG.  55.  —  THE    MUSCLES    OF    THE 
BODY. 


190 


PHYSIOLOGY   AND    HEALTH 


hands  and  feet  are  voluntary  muscles.  (2)  The  involun- 
tary muscles  are  not  controlled  by  the  will,  and  usually 
we  are  neither  aware  of  what  they  are  doing  nor  of  the 
fact  that  the  brain  is  giving  them  any  orders.  The 
muscles  of  the  stomach  are  involun- 
tary. 

Voluntary  Muscles.  —  There  are 
about  500  voluntary  muscles ;  each 
one  of  them  has  been  named,  but 
we  are  more  interested  here  in  the 
way  they  work  than  in  their  names. 
They  are  of  various  sizes  and  shapes, 
as  is  shown  in  Figures  54  and  55. 
Each  of  those  muscles  pulls  in  the 
direction  in  which  the  lines  in  the 
figure  are  drawn. 

A  muscle  seems  to  be  a  solid  mass, 
but  looked  at  under  a  microscope  it 
proves  to  be  made  up  of  an  immense 
number  of  threads,  called  muscle 
fibers.  Figure  56  shows  the  ar- 
rangement of  these  fibers  and  shows 
that  they  are  striped.  The  fibers 

They 
little 


FIG.  56.  —  A  MUSCLE. 

A,  the  whole  muscle,  with   run  lengthwise  of  the  muscle. 

tendons     at     the     end,  -,  , ,  •    j 

showing  its  division  into   are     bound     together     into 
bundles ;  B,  one  of  the   bundles ;   even  the  smallest  muscle 

bundles  of  muscle  fibers ;     contamg  a  number  of  bundles.       The 

binding  substance  that  holds  the 
muscles  together  so  firmly  is  called  connective  tissue, 
a  name  that  is  easily  explained  when  one  knows  that 
this  tissue  is  found  all  over  the  body,  connecting  all 


C,  a  single  muscle  fiber. 


K    « 
B     H 


d  O 

5  > 


ii 


!i«^\«H^^l«ui^>:;^l!lf|gi|M 

^ 


HOW  THE  BODY  IS  MADE  MOVABLE  191 

the  different  parts  and  helping  to  hold  each  one  in  its 
place. 

Minute  capillaries  run  among  the  muscle  fibers,  as 
shown  in  the  opposite  colored  illustration.  Through  the 
thin  walls  of  those  capillaries  the  fibers  take  from  the  blood 
the  material  they  need  (1)  to  furnish  energy  with  which 
to  do  their  work,  and  (2)  for  building  new  muscle  fiber. 
Through  the  muscle  bundles  there  also  run  nerve  fibers 
by  which  messages  come  from  the  brain,  which  controls 
the  action  of  the  muscle.  Each  muscle  has  its  own 
specific  work  to  do.  For  instance,  the  muscles  that  bend 
the  arm  have  no  other  work  to  do  than  to  bend  it ;  they 
do  not  even  straighten  the  arm,  that  being  the  work  of 
another  set  of  muscles.  In  the  arm  and  hand  there  are 
over  fifty  different  muscles,  by  which  it  may  be  moved  in 
as  many  different  ways. 

Involuntary  Muscles.  —  When  a  boy  decides  to  train 
his  muscles,  to  make  them  strong  and  supple,  he  never 
thinks  of  the  vast  number  of  involuntary  muscles  that 
help  to  form  the  walls  of  most  of  the  tubes  of  the  body, 
like  the  stomach,  the  intestines,  the  arteries ;  nor  does 
he  need  to,  for  they  get  sufficient  exercise  in  doing  their 
daily  work.  To  be  sure  they  are  more  sluggish  than  the 
voluntary  muscles,  do  not  respond  as  quickly  to  the  orders 
given  them ;  but  they  work  for  long  hours  at  a  time,  and 
some  of  them  remain  contracted  for  a  long  time,  in  a  way 
that  none  of  the  voluntary  muscles  can  imitate.  They 
churn  the  food  in  the  stomach  and  drive  it  along  through 
the  intestines,  they  pump  the  blood  from  the  heart  to  all 
parts  of  the  body,  control  the  flow  of  blood  in  the  blood 
vessels,  and  do  a  great  deal  of  other  work  on  which  the 


192 


PHYSIOLOGY   AND   HEALTH 


life  of  our  bodies  is  absolutely  dependent.     In  that  respect 
they  are  even  more  important  than  the  voluntary  muscles ; 

but  since  they  are 
not  under  the  con- 
trol of  our  wills  we 
cannot  give  them 
direct  help  in  doing 
their  work,  so  we 
have  less  need  to 
know  about"  them 
than  about  the  other 
muscles.  In  appear- 
ance they  are  very 
different  from  the 
striped  (voluntary) 
muscles ;  they  are 
made  up  of  un- 
striped  fibers,  which 
are  bound  together 
into  flat  masses. 

What  the  Bones  Do 

Why  Bones  Are 
Needed.  —  The  vol- 
untary muscles 
would  be  of  no  use 
to  us  if  they  were 

n°^  Cached   to   the 

bony  framework  of 
the  body.  It  is 

FIG.  57. -THE  HUMAN  SKELETON.  necessary     to     knOW 


HOW  THE  BODY   IS  MADE  MOVABLE 


193 


Spinal  Cord 


more  about  the  bones  before  considering  how  the  muscles 
act,  since  both  of  them  are  involved  in  every  motion  we 
make.  An  adult  has  about  200  bones,  a  child  has  more 
than  200  ;  some  of  them  unite  as  he  grows.  The  bones, 
when  taken  together,  are  called  the  skeleton.  Figure  57 
shows  the  entire  skeleton 
with  the  exception  of  the 
28  bones  that  form  the 
skull.  (For  the  skull,  see 
Figure  59.)  As  a  pic- 
ture, the  skeleton  is  not 
attractive,  but  it  grows 
very  interesting  when  one 
remembers  how  much  is 
done  for  the  rest  of  the 
body  by  that  gaunt  bony 
framework. 

1.  The  bones   protect 
delicate  organs,  like  the 
heart  and  lungs. 

2.  They  support  the  soft  and  flexible  parts  of  the  body. 

3.  They  make  motion  possible  by  giving  muscles  the 
resistance  and  the  leverage  they  need. 

Location  and  Use  of  the  Principal  Bones.  —  The  spinal 
column,  which  is  in  the  middle  of  the  back,  is  a  strong 
support  for  the  whole  body;  it  consists  of  a  series  of 
small  bones  which  are  wonderfully  fitted  together  and 
are  capable  of  slight  motion.  In  a  grown  person  the 
spinal  column  or  backbone  is  about  28  inches  long. 
Each  one  of  the  bones  that  make  up  the  column  is  called 
a  vertebra  (plural  vertebras).  Figure  58  shows  two  of 


-Spinal  Cord 

FIG.  58.  —  Two  VERTEBRAE. 
The  spinal  cord  extends  through  them. 


194 


PHYSIOLOGY   AND   HEALTH 


them.  Notice  the  sharp-pointed  bones  that  appear  at 
the  right  side  of  that  figure  ;  they  are  what  we  feel  when 
we  run  our  fingers  down  our  backs.  The  rounded  surfaces 
of  the  vertebrae  are  on  the  inner  side  of  the  spinal  column. 
See  how  carefully  the  vertebrae  protect  the  delicate  spinal 
cord  that  runs  through  the  bony  channel  they  make  for  it. 
An  animal  that  has  a  spinal  column  is  called  a  verte- 
brate. Vertebrates  include  the  four-footed  animals  with 
which  we  are  familiar,  as  well  as  the  birds,  the  reptiles, 
and  the  fishes.  All  of  them  have,  like  man,  a  much 
greater  power  of  motion  than  would  be  possible  if  the 
long  spinal  column  were  made  up  of  one  solid  bone, 
which  would  necessarily  be  so  stiff  that  it  would  be  easily 

broken.  The  leg  bones 
are  not  nearly  as  long 
as  the  backbone,  but 
they  frequently  get 
broken,  while  we  rarely 
hear  of  a  break  in 
the  many-pieced  back- 
bone. 

The  skull,  a  rounded 
bony  box  that  rests 
on  the  spinal  column, 
is  shown  in  Figure  59  ; 
it  has  to  protect  some 
of  the  most  important 
parts  of  the  body  — 
the  brain,  the  eyes,  the  ears,  and  the  organs  of  taste 
and  of  smell.  Notice  how  few  openings  there  are  into 
the  skull,  and  how  carefully  they  are  placed. 


FIG.  59.  —  THE  HUMAN  SKULL. 


HOW  THE  BODY  IS  MADE  MOVABLE  195 

The  chest  is  another  larger  and  much  more  flexible  box 
of  bone ;  it  is  made  up  of  the  breast  bone  (the  sternum) 
in  front,  the  ribs  on  the  top  and  sides,  the  spinal  column 
on  the  back.  When  we  breathe,  this  chest  must  move, 
and  if  it  were  practically  solid  like  the  skull,  it  would 
not  answer  its  purpose  at  all.  Instead,  it  has  twelve 
pairs  of  slightly  movable  ribs,  all  attached  to  the  back- 
bone, and  all  except  the  two  lowest  pairs  attached  to 
the  breast  bone.  Those  two,  being  fastened  only  at  the 
back,  are  called  floating  ribs.  The  heart  and  the  .lungs 
are  securely  protected  inside  the  ribs,  which  also  give 
protection  to  portions  of  the  stomach  and  liver. 

The  strong  bones  at  the  hips  form  the  pelvic  girdle,  a 
partial  box  which  gives  support  to  the  organs  in  the  lower 
part  of  the  trunk. 

The  arms  and  legs  are  much  alike  in  their  bony  struc- 
ture ;  each  of  them  has  three  bones,  the  longest  and  the 
strongest  single  bones  in  the  body;  they  are  constantly 
in  motion,  and  they  have  to  be  strong  enough  to  bear 
great  strains.  One  of  the  bones  that  is  often  broken  by 
a  fall  on  the  point  of  the  shoulder  is  called  the  collar  bone 
(clavicle).  Notice  in  Figure  57  how  it  stands  up  above 
the  rest  of  the  chest  bones ;  it  is  easy  to  see  why  it  gets 
broken. 

QUESTIONS 

1.  Tell  one  important  way  in  which  men  and  animals  differ  from 
plants. 

2.  What  causes  a  muscle  to  move?    A  bone? 

3.  Of  what  are  muscles  composed?    To  what  are  they  attached? 

4.  How  does  a  tendon  differ  from  a  muscle? 

5.  Why  are  there  so  many  tendons  at  the  wrist? 


196  PHYSIOLOGY   AND   HEALTH 

6.  How  does  the  blood  needed  to  nourish  a  muscle  enter  the 
muscle  ? 

7.  Are  there  any  muscles  that  do  not  move  bones?     If  so,  what 
ones?    Are  there  any  that  are  both  voluntary  and  involuntary?     If 
so,  can  you  name  some  ? 

8.  Why  does  a  baby  have  to  learn  to  walk?    Why  does  a  little 
child  have  trouble  in  handling  his  spoon  and  fork? 

9.  What  happens  to  a  muscle  when  you  do  not  use  it  at  all  ?    When 
you  use  it  too  much?    What  happens  when  you  develop  one  set  of 
muscles  more  than  another? 

10.  If  the  muscles  below  your  elbow  should  be  paralyzed,  what 
motions  would  you  lose  ? 

11.  When  you  close  your  hand,  do  you  use  the  same  muscles  that 
you  used  when  you  opened  it  ? 

12.  Can  your  father  run  as  far  and  as  fast  as  you  can?    Can  he 
jump  as  far?     If  not,  why  not? 

13.  What  muscles  are  specially  exercised  when  playing  tennis? 
When  playing  basket-ball?    When  skating?     When  swimming? 

14.  If  one  of  your  muscles  had  to  be  interfered  with  and  you  had 
your  choice,  which  would  you  choose  —  a  voluntary  or  an  involuntary 
muscle  ?     Why  ? 

15.  How  many  bones  are  there  in  your  body  ?    How  many  can  you 
name  and  locate? 

16.  What   bones    protect    the    skull?     The    lungs?    The   heart? 
What  bones  support  the  stomach  and  abdomen?     What  bones  enable 
us  to  walk?    To  throw  a  ball? 

17.  How  many  openings  are  there  in  the  skull?    What  purpose  do 
they  serve? 


CHAPTER  VIII 
BONES   AND    JOINTS 

Bone  Structure.  —  The  different  bones  have  a  variety 
of  work  to  do;  all  of  them  are  made  as  light  as  is  con- 
sistent with  the  amount  of  strength  their  work  requires. 
The  long  bones  are  hollow  tubes,  which  makes  them 
much  stronger  than  the  same  amount  of  material  would 
be  if  formed  into  a  solid  cylinder.  Following  the  pattern 
of  these  bones,  hollow  tubes  are  now  used  at  many  points 
in  bicycles,  automobiles,  and  flying  machines.  The 
longest  bone  is  that  of  the  upper  part  of  the  leg  (the 
femur) .  Figure  60  shows  it  cut  open,  with  its  large,  solid 
but  spongy  ends  and  the  long,  hollow  shaft.  The  spaces 
are  filled  with  marrow.  In  the  marrow  contained  in  the 
spongy  ends,  red  corpuscles  are  made.  Men  have  never 
discovered  any  way  in  which  to  get  more  strength  in 
proportion  to  the  weight  than  is  given  by  the  structure 
of  these  bones. 

The  expression  "  dry  as  a  bone  "  represents  the  notion 
many  people  have  of  the  bones ;  but  the  fact  is  that  they 
are  alive,  not  dead  and  dry.  To  keep  them  alive  and  well 
there  are  tiny  blood  vessels  that  run  into  them  through 
small  holes.  All  bones  have  nerve  connections ;  the 
nerves  in  the  teeth  which  make  them  ache  also  serve  a 
very  good  purpose. 

197 


198 


PHYSIOLOGY   AND   HEALTH 


Bone  Materials.  —  Bones  are  made  up  of  animal 
matter,  which  gives  them  strength,  and  of  hard,  brittle 
mineral  matter,  which  gives  them  stiff- 
ness. In  the  living  bone  the  two  are 
mixed  together  and  form  one  substance, 
which  is  about  two-thirds  mineral  and 
one-third  animal  matter.  If  a  bone  is 
put  on  a  hot  coal  fire  and  left  there 
for  half  an  hour,  the  animal  matter  will 
be  burned  out,  leaving  only  the  mineral 
matter  which  is  lime  and  will  not  burn. 
This  burned  bone  will  keep  its  original 
shape,  but  it  will  be 
light,  and  so  brittle  that 
it  can  be  crumbled  in 
the  fingers. 

It  takes  longer  to 
remove  the  mineral 
matter ;  this  is  done  by 
putting  a  bone  into  a 
dish  of  dilute  nitric 
acid.  In  a  few  days 
the  acid  will  have  dis- 
solved out  the  mineral 
hollow  matter  leaving  only  the 
animal  matter.  The 
bone  will  appear  un- 
or  shape,  but  it  will 
flexible  that  it  can  be  bent  readily. 


FIG.  60.  — THE  FEMUR 
CUT  LENGTHWISE. 

Showing     the 
shaft  and  the  spongy 
end. 


FIG.  61.  —  A  BONE 
FROM  WHICH  THE 
MINERAL  MATTER 
HAS  BEEN  RE- 
MOVED. 

Showing  its  flexi- 
bility. 


altered   in    size 
be  so   soft   and 

The  Baby's  Bones.  -  -  The  bones  of  a  baby  contain 
much  more  animal  matter  than  those  of  a  grown  man, 


BONES  AND  JOINTS  199 

so  they  are  much  more  easily  bent.  The  result  is  that 
the  baby  seldom  gets  a  broken  bone,  even  from  a  serious 
fall.  Those  pliable  bones  have  one  disadvantage  —  they 
cannot  safely  hold  much  weight,  for  they  are  likely  to 
get  bent  under  any  great  strain.  That  is  one  of  the 
reasons  why  a  young  baby  should  not  be  urged  to  stand 
on  its  feet  for  any  length  of  time.  Active  babies  like  the 
adventure  of  the  new  position ;  they  will  want  to  stand 
as  soon  as  their  bones  are  strong  enough  to  make  it  safe, 
and  it  is  best  not  to  coax  them  too  early.  Nor  is  it  good 
for  them  to  sit  all  day  in  a  carriage ;  they  need  exercise, 
and  if  placed  on  the  floor  or  on  a  bed,  they  find  many 
ways  of  kicking  and  squirming  and  creeping  which  give 
exercise  without  putting  too  much  weight  on  their  bones. 
Broken  Bones.  —  When  bones  are  broken  they  will 
grow  together  again,  provided  that  the  two  ends  are 
united  and  held  firmly  in  position  until  the  live  matter 
in  the  bone  can  produce  new  layers  of  bone  substance  at 
the  spot  where  the  break  came,  thus  finally  making  the 
bone  as  strong  as  ever.  When  a  doctor  "  sets  "  a  bone 
he  brings  the  broken  ends  together  and  binds  them 
tightly  in  splints,  so  that  the  reunited  bone  may  be 
straight  and  perfect.  It  takes  experience  to  tell  when 
the  parts  of  the  bone  are  rightly  adjusted,  and  a  phy- 
sician ought  to  be  called  at  once  before  the  parts  around 
the  bone  begin  to  swell,  thus  making  it  harder  to  set  it. 
Before  he  arrives,  place  the  patient  in  a  comfortable  posi- 
tion in  which  it  will  not  be  necessary  for  him  to  move 
the  broken  bone.  If  the  break  is  in  the  arm  or  leg,  it  may 
be  stretched  out  on  a  soft  pillow.  In  case  the  patient 
has  to  be  moved,  make  a  stiff  splint  of  a  cane  or  a  stout 


200  PHYSIOLOGY  AND   HEALTH 

stick  and  tie  the  broken  limb  around  with  splint  and  pil- 
lows (coats  will  do)  in  such  fashion  that  no  strain  will 
come  on  the  broken  ends  of  the  bone. 

The  broken  bones  of  young  people  often  unite  in  three  or 
four  weeks  ;  with  older  persons  it  takes  longer.  Elderly 
people  have  an  excess  of  mineral  matter  in  their  bones, 
making  them  brittle.  A  fall  that  would  only  bruise  an 
active  boy  is  likely  to  result  for  his  grandfather  in  broken 
bones. 

Young  people  sometimes  have  a  form  of  fracture  in 
which  the  bone  is  slightly  split  instead  of  being  actually 
broken  across.  If  you  bend  a  dry  stick,  it  will  break; 
but  if  you  bend  a  green  or  live  stick,  it  will  bend  and  be 
likely  to  split  a  little  without  actually  breaking.  Such 
a  fracture  of  a  bone  is  called  a  "  green  stick  fracture  " 
and  it  is  often  overlooked  for  some  time. 

If  the  bone  is  broken  in  such  a  way  that  it  has  cut 
through  the  skin,  this  is  called  a  compound  fracture ;  it 
is  more  serious  than  a  simple  fracture,  because  there  is 
danger  that  disease  germs  may  get  in  through  the  wound. 
If  a  doctor  cannot  be  secured  promptly,  it  is  best  to  wash 
any  dirt  away  from  such  a  wound,  using  clean  water,  pref- 
erably hot  water  that  has  been  well  boiled  in  order  to  kill 
all  germs.  Then,  if  available,  use  some  weak  carbolic  acid 
or  tincture  of  iodine  to  wash  the  wound,  covering  it  with 
a  clean  cloth.  Do  not  touch  with  the  fingers. 

Misshapen  Bones.  —  Many  of  the  bones  of  the  body 
become  misshapen  through  improper  use  ;  but  the  stooped 
shoulders  and  slouching  gait  that  we  often  see  are  more 
frequently  due  to  badly  trained  muscles  than  to  any 
trouble  with  the  bones  themselves.  The  bones  most 


BONES  AND  JOINTS  201 

often  deformed  are  those  of  the  feet.  The  feet  would  be 
really  beautiful  and  shapely  if  they  were  not  deformed 
by  the  constant  use  of  improper  shoes.  In  the  olden 
days  most  people  went  barefoot  except  on  Sundays  and 
holidays,  and  their  shoes  were  made  by  a  cobbler  with 
some  reference  to  the  shape  of  their  feet.  Now  we  buy 
our  shoes  "  ready  made/'  and  too  often  they  are  selected 
more  because  they  look  fashionable  than  because  they 
fit  the  shape  of  our  feet. 

Shoes  that  Deform.  —  There  are  only  a  few  dozen 
different  sizes  and  shapes  to  be  had  in  shoes,  and  into 
them  have  to  be  fitted  and  cramped  hundreds  of  different 
shaped  feet.  Not  all  people  are  so  foolish  as  to  wear 
shoes  too  small  for  them,  but  unfortunately  a  shoe  that 
fits  one  part  of  the  foot  may  be  too  large  or  too  small  for 
another  part.  Hence  many  ill-fitting  shoes  are  worn, 
with  the  result  that  few  grown  people  have  feet  that  are 
free  from  corns  or  bunions  or  misshapen  toes.  Many 
ladies  who  are  justly  proud  of  their  shapely  hands  would 
be  much  abashed  if  a  change  in  the  styles  required  them 
to  wear  sandals  that  would  show  the  whole  foot,  so  mis- 
shapen have  improper  shoes  made  their  feet. 

Often  children  lay  the  foundation  for  much  trouble 
with  the  feet  by  trying  to  wear  shoes  that  are  too  narrow, 
on  the  mistaken  theory  that  if  they  wear  shoes  that  are 
large  enough  their  feet  will  "  spread  out  "  and  grow  larger 
than  they  otherwise  would.  What  really  happens  is  that 
the  feet  grow  to  their  natural  size,  just  as  the  hands  do. 
If  they  are  cased  in  shoes  so  narrow  or  so  short  that  they 
cannot  grow  naturally,  then  they  will  gr®w  as  they  can ; 
the  toes,  instead  of  being  shapely  like  the  fingers,  will  get 


202  PHYSIOLOGY   AND  'HEALTH 

to  be  lumpy  balls,  with  bones  bent  out  of  shape,  as  one 
toe  lies  over  another  (see  Figure  62)  in  order  to  fit  into 
the  narrow  toe  space  of  some  attractive  shoe. 

People  talk  of  "  breaking  in  "  a  new  pair  of  shoes ; 
that  usually  means  persuading  their  feet  to  be  cramped 
in  a  new  spot;   before  long  the  worst  of 
the  discomfort  is  over,  but  that  is  not  the 
end  of  the  matter.     A  glance  at  Figures  62 
and  65  will  show  that  such  cramping  of  the 
feet  must  in  the  end  get  them  into  such 
condition  that  walking,  which  is  the  best 
all-around  exercise,  will  become  so  painful 
that  one  does  not  take  exercise  enough.    If 
you  wish  to  avoid  pain  and  have  comfort 
FIG.  62.  —  A  DE-  in  walking  when  you  become  a  man  or 
FORMED  HUMAN  woman,  be  sure  to  follow  the  rule  of  wear- 

The°figure  shows  a    lllg  ShO6S  that  BIe  long  en°Ugh> wide  enough, 

common  form  of  and  have  low  heels.     Flat  foot  is  becoming 
deformity    pro-  more  and  more  common :  it  is  not  easily 

duced     by     the  ,   ,          .      .  ,  J 

use  of  improper  cured  but  it  is  readily  prevented  by  a  few 
shoes-  simple  measures.     They  are  : 

1.  Wear  properly  shaped  shoes,  with  broad  toes  and  low 
heels. 

2.  Toe  in  or  put  the  toes  straight  in  front  when  walking. 

3.  Exercise  the  toes  by  rising  on  them  with  the  weight  on 
the  little  toes  as  well  as  on  the  great  toe. 

4.  Do  not  stand  still  for  long  periods  at  a  time. 

Walking  does  not  hurt  the  feet,  but  standing  still  for 
a  long  time  puts  too  much  strain  on  the  arches.  Those 
who  have  much  standing  to  do  should  accustom  them- 


BONES  AND  JOINTS 


203 


selves  to  put  their  weight  first  on  one  foot  and  then  on 
the  other  —  and  above  all  to  toe  in. 

Deformed  feet  may  be  produced  by  shoes  with  narrow 
toes  or  with  heels  so  placed  as  to  throw  the  weight  on 


FIG.  63.  —  THE  ARCH  OF  THE  FOOT. 

On  the  left  are  shown  the  bones ;    and  on  the  right  the  ligaments 
that  help  to  support  the  arch. 

the  toes.  Compare  the  shape  and  location  of  a  shoe  with 
a  "  French  "  heel  with  the  way  your  own  foot  is  made. 
How  could  one  fit  the  other  ?  You  may  think  the  French 
heel  looks  stylish,  but  it  is  likely  to  produce  pain  and  dis- 
comfort in  your  future  years. 
The  Arch  of  the  Foot.  - 
Our  feet  are  really  most 
beautifully  adapted  by  nature 
to  meet  the  strain  that  comes 
upon  them.  The  whole  foot 
does  not  rest  flat  upon  the 
.ground  but  touches  at  the 
toes  and  the  heel,  with  an 
arch  between  them  (Figure 
63).  The  weight  of  the  body 
comes  on  the  arch,  which  acts  like  a  spring  and  makes 
walking  easy  and  elastic,  preventing  jars  and  reducing 


FIG.  64.  —  A  PROPERLY  SHAPED 
SHOE. 


204 


PHYSIOLOGY   AND   HEALTH 


fatigue.  As  long  as  the  arches  remain  well  bent  the 
gait  is  springy  and  walking  is  easy  and  pleasurable. 
If  a  person  will  wear  properly  shaped  shoes,  and  will 
walk  with  his  toes  straight  forward  or  even  "  toeing 
in  "  a  little,  he  may  expect  to  keep  the  arches  in  good 
condition.  But  if  he  wears  shoes  that  are  too  tight  or 

are  improperly  shaped, 
or  if  he  gets  into  the 
habit  of  "  toeing  out  " 


FIG.  65.  —  THE  BONES  OF  THE  FOOT. 
On  the  left  is  shown  a  properly  shaped  foot, 
and  on  the  right  is  shown  the  distortion 
produced  by  improper  shoes. 


FIG.  66.  —  THE  IMPRINT  OF  THE 
FOOT  UPON  A  FLAT  SURFACE. 

The  normal  foot  is  shown  on  the 
left,  and  the  imprint  of  a  flat- 
footed  person  on  the  right. 


when  he  walks,  the  arches  are  likely  to  give  way  after  a 
time  and  he  finds  himself  with  the  trouble  called  "  flat 
foot,"  or  "  fallen  arch."  Then  all  his  pleasure  in  walking 
is  gone,  and  even  when  sitting  still,  he  suffers  more  or 
less  constant  pain. 

Recruits  for  the  army,   the  police  force,   and  other 


BONES  AND  JOINTS 


205 


organizations  that  require  men  who  are  able  to  drill  and 
to  work  hard  are  liable  to  rejection  for  flat  foot. 

A  Test  for  Flat  Foot.  —  Young  people  do  not  usually 
have  "  flat  foot/'  they  merely  prepare  for  cases  of  it  in 
later  life ;  but  it  is  worth  while  to  test  one's  feet  for 


FIG.  67.  —  VERTEBRA. 
Showing  cartilaginous  cushions  between  the  vertebrae. 

it  if  there  is  occasion  to  suspect  that  the  arches  are 
falling.  A  surgeon  gives  the  following  simple  test  which 
everybody  can  apply;  if  you  try  it  and  think  you 
detect  trouble,  you  had  better  ask  your  doctor  to  test 
the  arches  for  you.  Test :  Put  a  little  water  into  a 
basin,  and  step  into  it ;  then  while  the  sole  of  your  foot 
is  moist  stand  on  a  piece  of  blotting  paper.  Figure  66 
shows  the  pattern  that  your  foot  ought  to  make,  and  beside 


206 


PHYSIOLOGY   AND   HEALTH 


it   the  pattern  that  a  foot  ought  not   to  make.     Test 
both  feet. 

Cartilage  in  the  Framework.  —  At  various  points  in 
the  framework  of  the  body  we  find  instead  of  stiff  bones 
a  tough  but  flexible  substance  called  cartilage.  The 
entire  framework  of  the  outer  ear  is  of  cartilage;  and 
cartilage  is  used  to  unite  the  ribs  with  the  breastbone 
(it  can  stand  more  hitting  and  wrenching  than  a  bone 
could).  It  makes  an  elastic  cushion  between  the  verte- 
bra of  the  spinal  column ;  but  for  its  presence  there  we 
could  not  jump  about  without  danger  of  seriously  jarring 
both  the  spinal  cord  and  the  brain. 

How  the  Joints  Work 

Joints  Necessary  for  Motion.  -  -  The  place  where  two 
bones  are  united  is  called  a  joint;  there  are  immovable 
joints  at  which  the  bones  are  as  firmly  united  as  if  they 
made  one  bone  (certain  bones  of  the  skull  are  so  joined) ; 


FIG.  68.  —  BONES  OF  THE  KNEE  JOINT  WITH  SOME  OF  THEIR  LIGAMENTS 
SHOWN  FROM  THE  SIDE. 


BONES  AND  JOINTS 


207 


and  there  are  movable  joints,  which  allow  motion.  If  it 
were  not  for  the  latter  kind,  we  could  no  more  move  than 
a  statue  can.  The  joints  are  either  hinge  joints,  ball-and- 
socket  joints,  or  pivot  joints. 

Hinge  Joints.  —  The  joints  that  work  only  in  one 
direction  are  called  hinge  joints ;  they  open  and  close  as 
a  knife  blade  does  on  its 
hinge  ;  like  it  they  can  neither 
open  backwards  nor  sidewise 
nor  rotate.  The  joints  of 
the  fingers,  the  wrist,  the 
elbow,  the  ankle,  and  the 
knee  are  all  different  forms 
of  the  hinge  joint.  Figure 
68  shows  the  ends  of  two 
bones  (the  thigh  bone  and 
the  shin  bone)  which  make 
the  knee  joint ;  see  how  they 
are  shaped  to  fit  each  other 
for  movement  forwards  and 
back. 

The  shape  of  these  two 
bones  would  not  allow  them 
to  move  on  eac"h  other  side- 
wise,  but  would  admit  of  their 
moving  backwards,  which 
would  be  very  startling.  That 

does  not  happen  because  they  are  held  in  their  rightful 
position  by  the  ligaments,  formed  of  tough,  flexible  con- 
nective tissue,  which  pass  over  the  joint  from  bone  to 
bone,  and  hold  the  bones  together.  Figure  69  gives  an 


FIG.  69.  —  KNEE  JOINT  FROM 
BEHIND. 

The  ligaments  connecting  the  bones 
are  shown. 


208  PHYSIOLOGY   AND   HEALTH 

indication  of  the  way  in  which  the  ligaments  are  inter- 
laced ;  they  hold  the  joints  so  firmly  and  yet  so  loosely 
that  while  the  joints  have  much  freedom  of  movement  they 
rarely  get  out  of  place.  The  muscles  also  help  to  hold 
the  bones  in  position  by  the  manner  in  which  their  ten- 
dons pass  over  the  joints. 

The  hinges  of  a  knife  are  often  so  stiff  that  it  is  hard 
to  open  the  blade ;  yet  the  hinge  joints  in  our  bodies  are 
so  adjusted  that  we  are  never  conscious  (except  in  cases 
of  accident  or  illness)  of  difficulty  or  friction  in  moving 
them.  In  the  first  place  the  ends  of  the  bones  are  so 
smooth  and  so  rounded  that  they  work  together  easily; 
then  each  one  of  them  has  a  thin  covering  of  smooth, 
soft  cartilage ;  and  there  is  also  a  thin  membrane  around 
each  joint  which  produces  a  liquid,  about  as  thick  as  the 
white  of  a  raw  egg,  that  keeps  the  ends  of  the  two  bones 
moist. 

Muscles  at  Hinge  Joints.  —  A  muscle  can  only  shorten 
itself ;  if  it  needs  to  be  lengthened,  that  must  be  accom- 
plished by  the  action  of  another  muscle,  which  lengthens 
the  first  one  by  shortening  itself.  Most  of  our  muscles 
are  arranged  that  way,  in  pairs ;  the  pair  are  called  an- 
tagonistic muscles  because  they  do  their  work  in  opposite 
directions ;  that  is,  when  one  shortens,  it  lengthens  the 
other. 

Ball-and-Socket  Joints.  —  In  the  ball-and-socket  joint, 
one  bone  has  a  rounded,  ball-like  head  and  the  other  a 
rounded  cavity  or  socket,  into  which  the  head  of  the  first 
bone  fits.  The  ball  can  move  in  any  direction  in  the 
socket,  and  that  makes  this  kind  of  joint  a  very  freely 
moving  one.  There  are  only  two  pairs  of  large  ball-and- 


BONES  AND  JOINTS 


209 


The  figure  shows 


socket  joints,  one  at  the  shoulders  and  the  other  at  the 
hips.  Figure  70  shows  the  bones  that  form  the  shoulder 
joint  as  they  look  with  the  skin,  muscles,  and  ligaments 
removed.  There  is  a  very  shallow  cup  in  the  shoulder 
blade  (scapula),  and  the  upper  end  of  the  arm  bone 
(humerus)  is  rounded  and  fits  into  it. 
two  bony  projections  over  the 
joint  which  limit  the  extent 
to  which  the  ball  can  move 
in  that  direction ;  but  even 
though  thus  limited  the  arm 
at  the  shoulder  has  very  free 
motion  in  all  directions. 

The  ball-and-socket  joints, 
like  the  hinge  joints,  have  a 
smooth  cartilage  and  a  lubri- 
cating fluid.  The  bones  are 
also  held  in  place  by  liga- 
ments. The  shoulder  has 
one  large  ligament,  a  loose, 
leathery  sac,  shown  in  Figure 

71,  which  is  fastened  to  the  shoulder  blade ;  it  passes  over 
the  joint  in  such  a  way  as  to  cover  it  on  all  sides.  Its 
other  end  is  attached  to  the  arm  bone  and  helps  hold  the 
rounded  bone  of  the  arm  in  the  socket.  There  are  also 
strong  muscles  that  completely  cover  the  joint.  The  ten- 
dons from  the  great  shoulder  muscles  pass  over  the  joint 
and  are  attached  to  the  bone  of  the  arm,  thus  making  a 
strong  connection  that  helps  hold  the  ball  in  the  socket 
even  under  great  strain. 

The  hip  joints  have  deeper  sockets  and  their  motion 


FIG.  70.  —  THE  BONES  OF  THE 
SHOULDER  JOINT. 


210 


PHYSIOLOGY   AND   HEALTH 


is  not  quite  so  free  as  is  that  at  the  shoulders.  Where 
the  fingers  and  the  thumb  join  the  hand  there  are  joints 
which  are  sometimes  referred  to  as  modified  ball-and- 
socket  joints.  They  are,  however,  very  differently 
shaped  from  those  at  the  shoulder  and  hips. 

Evidently  ball-and-socket  joints  require  a  larger  num- 
ber of  muscles  than  the  hinge  joints,  since  they  may  be 

asked  to  move  in  nearly 
every  direction.  Figure 
55  gives  some  impression 
of  the  number  found 
around  the  shoulder  j  oint . 
Pivot  Joints.  —  There 
is  a  third  type  of  joint 
in  the  body,  called  a 
pivot  joint,  because  one 
of  the  bones  remains 
stationary  and  the  other 
one  moves  around  it ; 
WITH  the  joint  that  enables  us 

THE  LIGAMENTS  THAT  HOLD  THE  BONES    to  rotate  the  head  is  One 

of   that    kind,    and    the 

one  at  the  elbow  that  enables  us  to  turn  the  hand  over 
is  another. 

How  Joints  Are  Injured.  —  It  is  seldom  that  bones 
are  broken  at  a  joint  because  the  joint  will  pull  apart 
under  great  strain.  A  wrench  sometimes  pulls  the  ball 
of  the  arm  bone  out  of  the  socket,  producing  a  disloca- 
tion; it  may  not  injure  the  bones  at  all,  but  it  is  likely 
to  tear  protective  coverings,  ligaments,  or  tendons  that 
hold  the  bones  together.  In  that  case,  one  has  a  sprain 


FIG.    71.  —  THE    SHOULDER    JOINT 


BONES  AND  JOINTS  211 

in  addition  to  the  dislocation.  A  physician  can  easily 
put  the  bones  back  into  position,  so  that  from  a  simple 
dislocation  there  would  be  temporary  discomfort  only; 
but  if  the  ligaments  and  tendons  are  torn,  the  injury  can- 
not be  repaired  quickly  because  they  are  not  plentifully 
supplied  with  blood  vessels.  Often  a  violent  strain  only 
tears  the  ligaments,  producing  a  sprain  without  any  dis- 
location ;  but  such  a  sprain  may  be  more  serious  and 
may  be  slower  to  heal  than  are  simple  dislocations  or 
broken  bones. 

Formerly  when  people  had  a  severe  sprain  in  the  ankle 
they  were  kept  in  bed  and  were  not  allowed  to  use  the 
sprained  ligaments  for  weeks.  This  resulted  in  making 
the  joint  stiff  and  painful  to  use.  Now  physicians  gen- 
erally bandage  the  sprained  joint  so  as  to  help  keep 
the  swelling  down  and  then  encourage  the  patient  to 
exercise  it  moderately;  the  result  is  better  circulation, 
which  will  produce  a  more  rapid  repair  of  the  injured 
parts. 

A  severe  sprain  requires  the  attention  of  a  physician; 
but  before  he  comes,  the  joint  should  be  raised,  for  this 
helps  keep  down  the  inevitable  swelling,  by  preventing 
the  blood  from  collecting.  Applications  of  either  very 
hot  or  very  cold  water  should  be  made ;  and  sometimes 
both  are  used,  hot  water  being  followed  by  cold  to  pro- 
duce a  stimulus.  If  the  injury  is  too  slight  to  require 
the  care  of  a  physician,  it  is  still  best  to  give  it  the  treat- 
ment above  suggested.  Massage  (i.e.  rubbing)  is  also 
very  effective,  as  it  increases  the  blood  supply  and  keeps 
the  joint,  which  is  not  having  its  normal  amount  of 
exercise,  from  getting  stiff. 


212  PHYSIOLOGY   AND   HEALTH 

QUESTIONS 

1.  Compare  a  baby's  bones  with  those  of  an  adult.    Why  is  there 
such  a  difference? 

2.  Is  there  any  blood  in  bones?     If  so,  how  does  it  enter  them? 

3.  Can  you  give  any  reason  why  the  femur  is  stronger  than  the 
humerus  ? 

4.  Why  is  the  frame  of  a  bicycle  made  of  hollow  tubes  instead  of 
solid  bars? 

5.  What  happens  when  the  animal  matter  is  taken  out  of  a  bone  ? 
When  the  mineral  matter  is  taken  out  ? 

6.  When  a  bone  is  broken,  how  does  nature  repair  the  damage? 
What  is  necessary  in  order  that  this  may  occur?    What  happens  if  a 
broken  bone  is  allowed  to  "set"  in  a  wrong  position? 

7.  If  you  were  with  a  friend  in  the  woods  and  he  should  break  his 
arm,  what  would  you  do?    What  could  you  use  as  a  splint?    As 
bandage  and  padding?    As  a  sling? 

8.  If  both  you  and  your  father  should  break  a  leg  at  the  same 
time,  which  would  probably  get  well  first  ?     Why  ? 

9.  Why  does  an  old  man  not  dare  to  jump  from  a  fence  that  you 
are  not  afraid  to  jump  from? 

10.  How  may  the  bones  become  misshapen?    When  is  this  most 
apt  to  occur?    How  may  it  be  avoided ? 

11.  What  may  happen  if  you  wear  shoes  that  are  too  tight?    Shoes 
that  are  too  short? 

12.  Name  some  classes  of  people  who  are  likely  to  have  "  flat  foot." 

13.  If  you  had  a  hinge  joint  at  the  neck,  what  motions  could  you 
make  with  your  head  ?     What  motions  could  you  not  make  ? 

14.  If  you  had  no  joint  at  your  knee,  could  you  walk?     Try  it  and 
see.     Could  you  walk  if  you  had  no  hip  joint? 

15.  Can  the  bones  at  a  joint  move  of  their  own  accord?    What 
must  move  them? 

16.  Which  kind  of  joint  has  more  muscles,  a  hinge  joint  or  a  ball- 
and-socket  j  oint  ?    Why  ? 

17.  Which  would  recover  more  quickly  from  a  sprain,  a  person  who 
rested  the  joint  or  one  who  used  it  as  soon  as  possible? 


CHAPTER   IX 
EXERCISE:     STRENGTH   AND    GRACE   OF  BODY 

Taking  Exercise.  —  When  people  "  take  exercise," 
what  parts  of  the  body  get  the  exercise?  Almost  all 
parts  of  the  body  share  in  it  to  some  extent ;  the  parts 
directly  concerned  are  the  bones,  the  ligaments  and 
tendons  at  the  joints,  and  the  muscles,  including  not  only 
those  used  in  walking,  or  whatever  the  exercise  may  be, 
but  also  the  heart  muscle  arid  the  breathing  muscles. 
The  nervous  system  also  gets  exercise,  for  it  directs  the 
action  of  all  those  muscles. 

Both  nerves  and  muscles  benefit  by  having  plenty  of 
work  to  do.  The  muscles  grow  stronger  and  the  nerves 
become  able  to  do  their  work  with  more  certainty  and 
speed.  The  pitching  of  a  baseball  and  the  playing  of  a 
violin  require  a  complicated  series  of  muscular  movements 
to  take  place  simultaneously,  each  one  so  nicely  gauged 
that  it  shall  balance  another.  So  we  practice  and  prac- 
tice ;  which  really  means  that  we  repeat  the  motions  so 
many  times  that  the  nervous  system  learns  just  how  to 
direct  the  making  of  them  perfectly.  The  muscles 
show  their  improvement  by  growing  larger  as  they  are 
used.  There  are  some  occupations  in  which  certain 
muscles  are  worked  very  hard,  while  the  rest  of  them  get 
little  exercise.  Which  muscles  are  developed  by  the  hod 
carrier,  the  stone  cutter,  the  bicycle  rider,  the  laundress, 

213 


214 


PHYSIOLOGY   AND   HEALTH 


the  gardener,  the  hammer  thrower,  the  oarsman?  Which 
muscles  do  each  of  these  occupations  leave  without  exer- 
cise enough? 

Corrective  Exercise.  —  Many  a  man  tends  to  get  bent 
over  with  his  work  or   acquire   some   muscular  habits 

that  make  him  ungrace- 
ful ;  he  cannot  change  his 
work,  perhaps,  but  he 
can  offset  its  bad  effects. 
Fortunately  a  few  min- 
utes of  well-directed  ex- 
ercise taken  regularly 
every  day  will  counteract 
the  effects  of  hours  of 
cramping  work.  Then 
too  we  all  need  some  gen- 
eral exercise  that  shall 
bring  into  play  those 
muscles  that  we  are  not 
using  regularly,  for  the 
really  strong  man  is  the 


FIG.  72.  —  THE  HERMIT  CRAB. 

A,  the  type  of  animal  from  which  the  her- 
mit crab  originally  came ;   B,  the  hermit 


crab,  showing  the  soft,  flabby  abdomen  one  who  has  developed 
produced  because  the  animal  thrusts  its  ^  Q£  ^  muscles.  Tnis 
abdomen  into  a  snail  shell  for  protection. 

is  particularly  necessary 

in  these  days  when  automobiles,  trolley  cars,  and  eleva- 
tors are  weakening  our  legs,  and  easy-chairs  and  ham- 
mocks are  weakening  our  backs.  It  is  time  for  us 
to  remember  what  befell  the  hermit  crab  (Figure  72). 
Originally  that  crab  was  fully  protected  by  a  hard  shell, 
but  when  it  acquired  the  habit  of  thrusting  its  abdomen 
into  the  shell  of  a  snail  for  protection,  it  ceased  to  use  its 


EXERCISE:    STRENGTH  AND   GRACE   OF  BODY     215 

own  shell  and  so  gradually  lost  it,  thereby  becoming  the 
flabby,  misshapen,  absurd  thing  it  now  is. 

Common  Sense  in  Exercise.  —  The  man  who  gives 
his  body  too  much  severe  exercise  is  a  little  more  foolish 
than  the  One  w*ho  takes  none  at  all.  The  first  is  likely  to 
die  in  middle  life,  as  many  athletes  do,  from  the  undue 
strain  that  he  puts  on  the  heart ;  the  second  may  live  to 
old  age  without  taking  exercise,  though  his  body  and  his 
mind  will  never  be  as  active,  never  accomplish  as  much 
as  they  might  have  done.  If  it  were  not  that  the  happy 
games  of  his  childhood  had  given  all  his  muscles  a  chance 
to  grow,  many  a  man  would  not  be  able  to  perform  his 
work ;  if  he  could  be  an  active  boy  again  for  even  fifteen 
minutes  a  day  he  would  feel  the  benefit.  We  should  all 
be  able  to  do  every  day  a  much  larger  amount  of  work 
than  we  think  possible  if  we  would  only  keep  the  body 
machine  in  proper  condition. 

Out-of-door  games  are  much  better  than  the  same 
amount  of  work  in  a  gymnasium.  From  listless  exercise 
of  any  sort  we  get  only  an  indifferent  amount  of  good. 
Walking  five  miles  a  day  would  be  sufficient  exercise 
for  a-  business  man,  but  poor  allowance  for  a  growing 
boy,  whose  instinct  tells  him  that  running  is  better  than 
walking.  There  is  much  work  in  a  house  or  about  the 
grounds  that  may  be  done  with  the  briskness  and  spring 
that  make  exercise  of  the  greatest  benefit. 

Many  a  college  student,  ambitious  of  distinction  in 
his  work,  has  tried  to  get  more  time  for  study  by  cutting 
down  his  time  for  exercise  ;  he  usually  finds  that  the  time 
he  gains  in  that  way  is  really  lost,  for  an  hour's  study 
after  exercise,  when  one's  mind  is  keenly  alert,  is  worth 


216  PHYSIOLOGY   AND    HEALTH' 

more  than  two  hours  of  listless  study,  with  wandering 
attention. 

Fatigue  from  Exercise.  —  A  man  who  is  taking  vio- 
lent exercise  may  feel  very  much  fatigued  long  before 
his  muscles  have  done  all  the  work  that  they  are  able 
to  do  without  discomfort.  It  is  not  because  his  joints 
are  weary  of  working  or  because  the  nervous  system  is 
tired  of  giving  commands ;  the  trouble  usually  is  due  to 
the  so-called  fatigue  poisons  that  are  made  by  the  muscles 
when  they  work.  At  first  the  poison  is  carried  off  as 
fast  as  it  is  made,  but  little  by  little  it  begins  to  accumulate 
in  the  system,  and  the  man  begins  to  be  distressed  by  it. 
The  heart  is  not  able  to  pump  the  blood  around  fast  enough 
to  carry  off  the  poison.  When  that  point  is  reached,  to 
go  on  exercising  only  increases  the  trouble ;  one  should 
stop  and  give  the  system  a  chance  to  get  righted. 

That  is  why  the  whole  system  is  tired  when  a  single 
muscle  is  cotnpletely  fatigued.  If  a  boy  takes  a  long,  hard 
walk,  he  cannot  come  home  and  study  to  advantage.  His 
elders  used  to  expect  him  to  do  it,  but  experiments  in 
many  laboratories  have  shown  that  the  boy  is  right  in 
saying  that  it  is  impossible.  In  laboratories  men  have 
apparatus  by  which  they  can  measure  accurately  the 
amount  of  work  that  a  muscle  can  do ;  they  find  that 
when  the  legs  are  tired,  the  muscles  of  the  fingers  cannot 
do  much  work ;  that  after  an  examination  the  muscles 
of  the  legs  cannot  do  as  much  work  as  they  could  when 
the  examination  began.  Stated  another  way,  this  means 
that  if  you  have  to  study,  you  must  not  play  too  long. 

In  cases  of  excessive  fatigue,  a  very  hot  bath,  not  more 
than  five  minutes  long,  will  help ;  it  should  be  followed 


EXERCISE:    STRENGTH  AND   GRACE   OF  BODY     217 

by  quiet  sleep,  for  during  sleep  the  body  can  recuperate 
faster  than  when  it  has  many  other  things  to  attend  to 
as  it  does  when  we  are  awake,  no  matter  how  quiet  we 
think  we  are  keeping. 

Well-directed  Exercise.  —  In  one  way,  taking  exercise 
is  like  taking  medicine ;  the  right  amount  of  medicine  is 
much  better  than  a  large  dose.  It  is  never  well  to  use 
the  muscles  as  hard  as  one  can ;  for  light,  regular  exer- 
cise actually  builds  the  body  up  better  than  the  lifting 
of  heavy  weights.  The  muscles  need  to  work,  and  then 
they  need  rest. 

One  good  rule  to  remember  is  :  Don't  spare  your  weak 
muscles.  They  are  the  ones  that  need  exercise.  If 
you  are  right-handed,  remember  to  do  with  your  left 
hand  certain  things  that  do  not  require  accurate  muscle 
control,  like  opening  doors,  lifting  bundles,  digging  in  the 
garden,  etc. ;  that  will  mean  adding  a  number  of  new  and 
willing  servants. 

Muscular  Stimulants.  —  The  only  real  stimulants  for 
healthy  muscles  are  exercise,  work,  and  active  play. 
There  was  a  time  when  the  word  "  stimulant  "  would  have 
suggested  immediately  the  use  of  some  form  of  alcoholic 
drink ;  people  knew  that  they  felt  more  powerful  after 
taking  a  little  alcohol,  so  they  thought  it  helped  to  make 
the  muscles  work.  Then  test  after  test  was  made,  in  the 
laboratories  and  in  active  work.  Alpine  climbers  were 
watched  to  see  how  much  work  they  could  do  with  alcohol 
and  how  much  without ;  many  experiments  were  made 
with  armies,  in  cold  countries  and  in  hot  countries ;  they 
tested  athletes ;  they  tested  ordinary  men,  day  after 
day.  The  testimony  was  all  against  the  use  of  alcohol, 


218  PHYSIOLOGY   AND   HEALTH 

for  it  was  found  that  alcohol  deceived  the  men  who  used 
it ;  although  they  felt  that  they  were  doing  more  with  it, 
they  were  usually  doing  from  10  per  cent  to  30  per  cent 
less. 

The  records  made  by  the  tobacco  users  have  also  been 
watched;  it  is  found  that  tobacco  never  favors  the 
growth  of  the  muscles.  In  some  universities  compara- 
tive records  of  smokers  and  non-smokers  are  kept ;  these 
show  that  non-smokers  gain  about  one-quarter  more  in 
height  and  girth  of  chest  during  their  college  course, 
than  the  smokers  gain ;  also  that,  taking  all  the  body 
measurements  into  account,  smokers  at  eighteen  are 
barely  the  physical  equals  of  seventeen-year-old  non- 
smokers. 

Strength  and  Grace  of  Body 

Strength  May  not  Give  Grace.  —  A  blacksmith  has 
strong  arms,  a  ditch  digger  strong  hands,  a  mail  carrier 
strong  legs;  with  all  this  strength  they  may  be  clumsy 
unless  some  exercise  is  given  to  the  muscles  not  used  in 
their  daily  work.  The  really  graceful  person  is  one  who 
has  all  his  muscles  properly  developed  and  whose  body 
is  well  poised,  whether  at  work  or  at  rest.  Rest  is  an 
active  process ;  it  is  not  gained  by  simply  letting  the  body 
relax.  The  boy  who  slouches  down  on  to  a  bench  after 
taking  his  turn  at  the  bat  is  really  not  getting  the  rest 
he  would  get  if  he  were  sitting  properly  and  is  not 
developing  a  graceful  body. 

Good  Poise  Is  Admired.  —  Good  poise  is  as  much 
needed  in  all  kinds  of  athletic  work  as  it  is  in  the  school- 
room, or  at  a  reception.  Do  you  wish  to  be  attractive  in 


EXERCISE:    STRENGTH  AND  GRACE  OF  BODY     219 


i : 


appearance?  You  cannot,  perhaps,  change  the  features 
of  your  face,  but  you  can  develop  a  graceful  body.  A 
graceful  carriage,  good  poise,  are  always 
more  admired  than  beautiful  features. 
The  person  who  is  stoop-shouldered,  who 
lounges  in  his  chair  or  at  his  desk,  who 
shuffles  his  feet  or  slouches  when  he  walks, 
is  not  admired  by  any  one.  Contrast  him 
with  the  West  Point  cadets ;  many  a  boy 
goes  to  West  Point  who  is  not  erect  and 
graceful,  but  day  after  day  he  is  put 
through  exercises  that  develop  his  muscles 
and  teach  them  to  work  together  smoothly. 
The  result  is  the  "  well  set-up,"  alert  man 
whom  everybody  admires.  It  is  not  only 
in  the  army  that  well-formed,  erect,  vigor- 
ous men  are  desired.  For  what  position 
or  occupation  would  not  such  a  man  have 
the  advantage  over  his  lounging  competi- 
tors? 

Common  Causes  of  Bad  Poise.  —  When 
a  person  stands,  sits,  or  walks  badly,  the 
cause  may  be  simply  heedlessness,  or  there 
may  be  some  trouble  with  the  bones  or  the 
muscles.  By  carelessness  in  childhood, 
when  the  bones  are  growing  and  harden- 
ing, they  sometimes  become  misshapen. 
The  bones  of  the  legs  may  bow  out,  or  the 
spine  may  get  a  forward  curve,  or  the  bones  of  the  fingers 
may  become  crooked.  After  twenty  years  of  age  there  is 
little  that  can  be  done  to  correct  any  misshapen  bones ; 


FIG.  73.  —  THE  SPI- 
NAL COLUMN. 

Showing  the  grace- 
ful curves. 


220  PHYSIOLOGY   AND   HEALTH 

they  must  remain  as  they  are  then,  possibly  growing 
worse  as  the  years  go  on.  Fortunately  misshapen  bones 
are  not  frequently  found.  Generally  the  defect  is  not 
in  the  bones  but  in  the  failure  of  the  muscles  to  use  them 
properly.  The  remedy  is  the  training  of  the  muscles,  and 
this  may  be  attempted  even  in  middle  life.  To  be  sure, 
progress  then  is  slow,  and,  when  you  are  grown  up,  it  will 
take  months  to  do  what  you  can  now  do  simply  with  a 
little  attention  to  the  position  assumed  at  work  and  at 
play.  The  child's  body  is  pliable  and  tends  to  mold  it- 
self to  the  shape  which  it  habitually  takes. 

It  seems  to  us  a  serious  matter  when  a  man  has  to 
have  a  broken  leg  set  in  the  woods,  far  away  from  a 
physician,  and  then  finds  that  because  it  was  set  wrong 
it  has  grown  permanently  crooked.  Yet  in  a  small  way 
we  are  doing  a  similar  thing  to  ourselves  when  we  con- 
tinually set  some  group  of  muscles  wrong ;  we  are  helping 
to  make  for  them  a  habit  of  action  or  inaction  that  can- 
not later  be  broken  without  much  effort  and  difficulty. 

Unused  muscles  become  small  and  weak.  If  we  get 
the  habit  of  relaxing  our  muscles  and  sitting  back  into  a 
comfortable  easy-chair,  we  are  weakening  the  muscles 
that  hold  our  backs  upright ;  they  will  lose  their  vigor, 
and  what  ought  to  be  a  natural  position  for  us  will  be- 
come difficult  and  uncomfortable.  Leaning  is  another 
foolish  habit ;  leaning  against  a  chair  or  a  counter  or 
whatever  support  may  be  at  hand  does  not  really  rest 
us.  One  tires  quickly  if  one  has  to  stand  still,  for  standing- 
keeps  the  same  muscles  contracted  for  a  long  time,  while 
when  one  is  moving  about  different  muscles  are  at  work. 
The  way  to  rest,  if  one  has  to  stand  for  any  length  of  time, 


EXERCISE:    STRENGTH  AND   GRACE  OF  BODY     221 

is  to  put  the  weight  first  on  one  foot  and  then  on  the  other. 
The  muscles  are  well  satisfied  with  that  kind  of  rest,  espe- 
cially if  the  weight  is  kept  forward  on  the  arch  of  the 
foot  and  the  feet  are  either  placed  straight  frontwards, 
or  with  the  toes  turning  slightly  inwards. 

Flat  chests  are  most  unattractive,  particularly  in  women  ; 
yet  all  girls,  when  they  are  young,  may  easily  acquire  a 
well-curved  chest.  It  is  most  readily  gained  by  using 
the  muscles  on  the  back  of  the  shoulders.  An  exercise 
which  calls  these  muscles  into  play  is  to  first  clasp  the  hands 
above  the  head,  and  then  behind  it.  The  best  exercises 
for  developing  the  chest  are  those  that  give  the  motions 
one  makes  in  pulling  candy.  See  how  you  can  introduce 
some  of  the  other  motions  into  your  games. 

Deformities  of  the  Spinal  Column.  —  Figure  73  shows 
the  beautiful  curves  that  make  the  spinal  column  so 
strong  and  yet  so  flexible.  Additional  curves  in  it  are 
very  undesirable.  By  careless  habits  many  people 
acquire  a  backward  curvature  of  the  spine  that  is  most 
unattractive,  and  like  other  deformities  the  outer  defect 
is  not  nearly  so  serious  as  the  inner  misadjustments.  Boys 
and  girls  have  it  in  their  power  to  determine  the  shape 
and  appearance  of  their  bodies  for  the  rest  of  their  lives. 

If  the  spinal  curve  in  the  neck  is  allowed  to  become  too 
great,  a  person  walks  with  head  thrust  forward  and  with 
stooping  shoulders ;  if  the  curve  in  the  lower  part  of  the 
back  is  accentuated,  the  abdomen  protrudes,  giving  a  very 
unpleasing  appearance.  Both  these  defects  are  easily 
avoided  by  correct  habits  in  standing  and  sitting.  The 
remedy  is  not  to  "  hold  in  "  the  abdomen,  or  to  do  some- 
thing queer  and  uncomfortable  to  the  shoulders.  Strain- 


222  PHYSIOLOGY   AND   HEALTH 

ing  does  not  put  the  body  back  into  poise ;  that  can  only 
be  done  by  correcting  the  root  of  the  difficulty,  that  is, 
by  straightening  out  the  unnecessary  curve  that  has  been 
put  into  the  spine.  One  direction  often  given  is,  stand 


FIG.  74.  —  A  BAD  AND  A  GOOD  POSTURE. 

Due  to  correctly  and  incorrectly  curved  spinal  columns.    Which  do  you  prefer  ? 
You  can  have  either. 

tall;    another   is,    always   keep   your  neck   pressed   back 
against  your  collar. 

Poise  in  Standing  and  Sitting.  —  Watch  yourself  when 
you  are  standing  to  see  whether  you  have  the  bad  but 
common  habit  of  standing  with  the  weight  on  the  heels. 
The  weight  should  be  on  the  arch  of  the  foot.  If  you 
have  difficulty  in  placing  the  weight  there,  try  to  carry  it 
still  further  forward  to  the  front  of  the  foot ;  you  will  then 
find  that  you  can  more  readily  transfer  it  to  the  arch. 


EXERCISE:    STRENGTH  AND   GRACE  OF  BODY     223 

In  the  army,  men  are  trained  to  sit  erect ;  when  you 
have  a  chance  to  see  an  army  officer  at  work  at  his  desk, 
you  will  not  see  him  slouched  over,  or  leaning  back  to 
find  a  "  comfortable "  position.  He  can  work  better 
when  sitting  up  and  paying  attention  to  his  work;  and 
he  has  discovered  that  he  can  rest  better  by  letting  the 
muscles  hold  the  body  up  than  when  some  of  them  are 
cramped  and  others  are  stretched  by  dropping  into  a 
half -reclining  position.  A  good  rule  as  to  position  is  this  : 
sit  erect  when  you  sit ;  lie  down  when  you  need  rest. 

How  to  Walk.  —  Walking  is  excellent  exercise  when 
done  properly.  The  most  common  fault  in  walking  is 
using  the  heels  too  much  and  the  toes  too  little.  Easy 
and  graceful  walking  requires  that  the  weight  of  the  body 
should  be  thrown  upon  the  ball  of  the  foot  as  it  touches 
the  ground.  When  the  heel  comes  down  first,  the  effect 
is  less  graceful  and  more  tiring,  and  that  method  is  partly 
responsible  for  broken  arches  and  flat  feet.  At  first 
one  may  find  it  tiresome  and  difficult  to  change  one's 
habit  of  walking ;  the  muscles  have  been  adjusted  to  the 
heel-first  gait.  A  little  persistence,  however,  will  result  in 
the  formation  of  habits  in  walking  which  will  prove  a 
lifelong  blessing. 

How  to  Exercise.  —  In  most  games  and  sports  the  arms 
and  the  legs  are  exercised.  It  is  important  not  to  forget 
the  muscles  of  the  trunk,  for  when  their  tone  is  good  they 
hold  the  important  organs  of  the  abdomen  in  place. 
Any  exercise  given  to  them  serves  a  double  purpose,  for 
it  also  promotes  the  circulation  of  the  blood  and  the 
lymph,  thus  providing  for  a  more  rapid  removal  of  the 
waste  products  from  the  body. 


224  PHYSIOLOGY   AND   HEALTH 

Ask  the  oldest  and  the  wisest  person  you  know  whether 
people  get  on  in  the  world  by  doing  easy  things  or  by 
doing  hard  things.  All  of  us  are  pleased  when  we  have 
learned  how  to  do  a  hard  thing  well ;  but  we  do  not  al- 
ways remember  this  when  the  hard  task  comes.  The 
way  to  take  hard  things,  in  games  or  in  study  or  in  exercise, 
is  with  a  dash,  going  out  toward  them  not  grudgingly,  but 
determined  to  get  out  of  them  all  the  good  there  is  in  them. 

The  Value  of  Games.  —  Active  games,  played  with  a 
will,  exercise  the  heart  and  the  lungs  and  at  the  same 
time  use  all  the  muscles ;  they  also  train  the  senses  and 
the  power  to  think  quickly  and  to  decide  rightly.  They 
are  ,good  training  for  life.  Young  people  who  excel  in 
games  and  sports  usually  enjoy  them;  those  who  do  not 
excel  need  to  learn  the  very  things  that  those  games  would 
teach.  In  the  olden  days,  when  nations  took  charge  of 
the  activities  of  their  young  people  to  insure  having  the 
right  kind  of  citizens  growing  up,  the  young  were  given 
as  careful  training  in  various  athletic  sports  as  in  any 
branch  of  learning.  No  excuses  were  accepted ;  if  a 
boy  "  did  not  like  "  some  exercise,  he  was  regarded  as 
defective  and  trained  in  it  with  particular  care. 

Exercises  for  Suppleness  and  Grace.  —  To  secure  a 
graceful  carriage  the  muscles  must  not  be  overdeveloped, 
and  their  development  must  be  well  balanced.  They 
must  be  strong  and  under  that  perfect  control  which 
comes  from  constant  use.  The  kind  of  exercises  best 
adapted  to  bring  this  about  are  such  as  the  following : 

Balancing  exercises,  like  walking  on  the  rails  of  a  rail- 
road track  or  on  any  narrow  board,  with  the  hands  hanging 
loosely  at  the  sides. 


EXERCISE:    STRENGTH  AND   GRACE   OF  BODY      225 

Dancing  of  all  kinds,  but  especially  those  types  of 
folk  dances  which  involve  the  use  of  the  arms  in  harmony 
with  the  legs. 

Jumping  forward  or  backward  or  to  the  side,  with  the 
knees  bent,  especial  care  being  taken  to  land  lightly 
rather  than  to  jump  far. 

Shifting  the  weight  of  the  body  rapidly ;  (1)  Step  for- 
ward on  the  right  foot,  raising  the  arms  (with  muscles 
relaxed)  at  the  sides,  and  hopping  on  the  right  foot ; 
then  step  forward  on  the  left  foot  and  hop  in  the  same 
way.  (2)  Step  lightly  a  long  step  to  the  right,  raising  the 
right  arm  with  the  elbow  and  wrist  slightly  bent  over  the 
head,  and  with  the  left  arm  curved  in  front  of  the  body ; 
then  change  the  position  of  the  hands  and  step  on  to  the 
left  foot  and  hop.  This  exercise  may  be  continued  alter- 
nately first  on  one  foot  and  then  on  the  other. 

QUESTIONS 

1.  Which  is  better  as  exercise,  work  or  play?    Give  reasons  for 
your  answer. 

2.  What  effect  does  exercise  have  on  the  muscles?    On  the  nerves? 
On  the  shape  of  the  body? 

3.  Name  some  kinds  of  work  that  are  apt  to  affect  one's  health 
and  bodily  proportions. 

4.  Tell  some  kinds  of  exercise  that  are  good  for  the  development 
of  the  arms,  the  back,  the  lungs ;  some  that  are  good  for  the  develop- 
ment of  all  parts  of  the  body. 

5.  What  happens  if  we  do  not  exercise  enough?    What  happens 
if  we  do  not  exercise  one  set  of  muscles  at  all?     Is  it  possible  to  exer- 
cise too  much? 

6.  What   is   meant   by    "fatigue    poisons"?     How   does   nature 
take  care  of  these  ? 

7.  Can  you  study  well  after  taking  moderate  exercise  ?    After  very 


226  PHYSIOLOGY  AND   HEALTH 

vigorous  exercise?    Can  you  work  well  after  studying  hard?    Can 
you  study  well  after  working  hard? 

8.  Which  will  make  the  better  business  man,  a  boy  trained  in 
games  requiring  accuracy  and  cooperation  with  others  or  one  whose 
play  is  spasmodic  and  unformed?     Which  will  make  the  better  stu- 
dent ?     The  better  soldier  ? 

9.  Which  can  probably  lift  the  heavier  weight,  a  ditch  digger  or  a 
postman?    Which  can  walk  farther?     Why? 

10.  If  some  of  your  muscles  are  weak,  do  they  need  rest  or  exercise? 

11.  Why  do  trainers  of  athletes  forbid  them  to  use  alcohol  or 
tobacco?    Why  do  the  big  railroad  companies  refuse  to  hire  young 
men  who  smoke  cigarettes? 

12.  How  does  excessive  exercise  of  one  set  of  muscles  affect  the 
body  ?    How  does  moderate  exercise  of  all  the  muscles  affect  the  body  ? 

13.  What  kinds  of  exercise  prevent  round  shoulders?     What  kinds 
prevent  weak  backs?    What  kinds  improve  the  action  of  the  lungs 
and  heart? 

14.  What  happens  to  a  boy  or  girl  who  sits  in  a  bad  position  ?    What 
should  such  a  boy  or  girl  do  ?    Which  is  more  restful,  sitting  properly 
or  sitting  badly?    Does  this  seem  always  to  be  true?    Give  reasons 
for  your  answer. 

15.  If  you  carry  your  books  always  on  one  arm,  what  is  apt  to 
happen  to  your  body?     If  one  shoulder  is  lower  than  the  other,  what 
exercise  should  you  take  to  counteract  this  defect?     If  you  are  in 
the  habit  of  holding  your  head  thrust  forward,  how  can  you  overcome 
this  fault? 

16.  Some  time  try  the  experiment  of  standing  in  front  of  a  mirror 
in  your  usual  position.     Without  moving  your  feet,  see  how  much 
taller  you  can  make  yourself.     Which  position  do  you  like  best  ?     Try 
the  same  experiment  sitting  in  a  chair,  also  sitting  on  the  floor.     Do  you 
get  a  correct  position  in  each  case  ? 

17.  If  you  get  in  the  habit  of  relaxing  the  muscles  of  the  back, 
what  effect  has  this  on  the  lungs?    On  the  stomach?    What  effect 
on  the  general  health? 


CHAPTER  X 
REMOVAL   OF   BODY   WASTES 

Preventable  Poisoning.  —  Few  people  appreciate  the 
extent  to  which  poisonous  wastes  are  produced  in  their 
bodies  as  the  necessary  result  of  life  processes,  or  the 
extent  to  which  illnesses,  both  slight  and  serious,  are  due 
to  the  accumulation  of  poisons  in  the  body.  In  fact  if 
we  include  together,  under  one  head,  the  poisons  produced 
in  our  bodies  by  disease  germs  and  those  manufactured 
by  the  body  itself  as  it  works,  there  would  be  no  exag- 
geration in  saying  that  the  great  majority  of  all  deaths 
are  due  to  poisoning ;  and  in  many  cases  to  preventable 
poisoning. 

Production  of  Wastes.  —  A  locomotive  always  pro- 
duces waste  products  when  it  is  drawing  a  train  of  cars. 
Some  of  these  wastes,  the  smoke  and  the  hot  gases, 
pass  out  of  the  smokestack;  others,  chiefly  ashes,  fall 
into  the  firebox  and  from  there  on  to  the  track.  If  the 
fireman  did  not  keep  the  grate  free  so  that  the  ashes  could 
pass  through,  or  if  the  smokestack  were  stopped  so  that 
the  smoke  and  the  gases  could  not  escape,  the  fire 
would  go  out  and  the  train  would  come  to  a  stop. 

The  body  is  in  much  the  same  position ;  every  part  of 
it  produces  some  waste  as  it  works.  Food  is  the  chief 
source  of  these  wastes,  and  they  are  produced  when  the 
food  is  oxidized  (burned)  in  the  body.  The  living  tissues 

227 


228  PHYSIOLOGY   AND   HEALTH 

are  being  built  up  and  renewed  by  our  foods,  and  the  foods 
are  also  used  to  give  us  heat  and  energy.  When  food  is 
used  for  any  of  these  purposes,  it  is  broken  up,  and  from 
it  come  various  substances  that  must  be  gotten  rid  of, 
just  as  the  ashes  and  smoke  must  be  removed  from  the 
locomotive.  From  our  carbohydrates  and  fatty  foods 
the  wastes  are  carbon  dioxid  and  water;  from  our  pro- 
teins the  wastes  are  carbon  dioxid  and  water  and  a  sub- 
stance called  urea,  together  with  small  quantities  of 
various  poisons.  When  the  muscles  work,  they  also 
produce  another  kind  of  poison  that  has  been  called 
fatigue  poison.  All  these  substances,  together  with 
other  wastes,  are  removed  by  the  several  means  that 
nature  has  provided. 

How  the  Body  Wastes  Are  Removed 

From  Intestines  and  Liver.  —  A  portion  of  every  meal 
we  eat  consists  of  food  that  is  either  indigestible  or  un- 
digested. There  are  also  the  wastes  that  have  been  taken 
from  the  blood  by  the  liver,  and  sent  with  the  bile  into 
the  intestine.  All  the  waste  matter  finds  its  way  into 
the  large  intestine  where  there  are  always  bacteria  ready 
to  cause  it  to  putrefy ;  it  then  becomes  a  source  of  dan- 
ger if  it  is  allowed  to  collect.  Safety  requires  that  this 
waste  should  be  expelled  once  or  twice  a  day  at  a  regular 
hour. 

From  the  Lungs.  —  Carbon  dioxid  and  water  are  con- 
stantly passing  off  from  the  lungs. 

From  the  Skin.  —  Everybody  knows  that  waste  matter 
is  given  off  by  the  skin,  for  the  odor  of  the  perspiration, 
especially  when  one  is  working  hard,  shows  that  it  con- 


REMOVAL  OF  BODY  WASTES  229 

tains  waste  products.  What  is  perspiration?  It  looks 
like  water  as  one  sees  it  standing  in  thick  drops  on  the 
forehead,  when  the  day  is  very  hot.  Dissolved  in  that 
water  are  waste  products  which  the  body  is  able  to  get 
rid  of  through  the  skin. 

Perspiration  is  being  thrown  off  all  the  time,  all  over 
the  body,  even  in  the  winter  and  even  when  we  are  asleep. 
Usually  we  do  not  notice  it  because  the  perspiration 
(called  insensible  perspiration)  evaporates  from  the  skin 
as  fast  as  it  is  formed.  This  can  be  proved  by  holding 
the  hand  tightly  closed  for  a  few  minutes;  you  will 
notice  that  the  palm  becomes  moist  with  the  perspiration 
that  could  not  evaporate  from  the  closed  hand.  When  it 
forms  faster  than  it  can  evaporate,  then  it  collects  on  the 
skin  and  we  say  that  we  are  sweating  because  we  can  see 
and  can  feel  the  sweat  drops. 

How  the  Kidneys  Remove  Wastes 

What  the  Kidneys  Do.  —  The  most  important  of  all 
the  waste  products  from  the  protein  portion  of  our  food 
is  the  substance  called  urea.  The  body  cannot  work 
unless  the  urea  formed  is  constantly  removed ;  to  accom- 
plish this,  it  is  necessary  that  both  the  liver  and  the  kid- 
neys work  together.  First  the  liver  turns  the  waste 
products  from  our  protein  food  into  urea ;  this  is  then 
taken  by  the  blood  to  the  kidneys,  whose  chief  business 
is  to  remove  it  from  the  body.  Through  the  kidneys  the 
blood  also  gets  rid  of  much  of  the  water  that  is  no  longer 
of  use ;  and  they  are  also  able  to  help  other  organs  of  the 
body  to  dispose  of  special  poisons.  Drinking  plenty  of 
water  every  day  helps  the  work  of  the  kidneys.  Water 


230  PHYSIOLOGY   AND   HEALTH 

never  clogs  the  system ;  it  is  readily  disposed  of,  and  it 
makes  easier  the  work  of  every  organ  that  shares  in  the 
work  of  excretion. 

Importance  of  Their  Work.  —  The  kidneys  are  small 
organs.  There  are  two  of  them,  usually  a  little  different 
in  shape.  One  would  never  imagine  from  looking  at  them 
that  they  had  such  important  work  to  do.  Sometimes 
other  organs  that  we  consider  absolutely  necessary  to 
life,  like  the  stomach,  have  been  removed  and  the  body 
has  gone  on  working  without  them.  But  the  kidneys, 
like  the  heart,  have  no  substitutes  standing  by  ready  to 
do  their  work  if  they  should  fail.  The  skin  can  help 
them  out  a  little,  the  intestines  can  give  them  a  still 
smaller  amount  of  help  ;  but  if  their  work  remains  undone, 
even  for  a  few  hours,  poisons  accumulate  in  the  body  and 
death  must  result.  Slight  disturbances  of  the  work  of 
the  kidneys  have  serious  effects;  and  most  of  these  are 
either  avoided  or  at  least  lessened  by  the  simple  expedient 
of  drinking  sufficient  water. 

How  the  Kidneys  Work.  —  The  kidneys  lie  behind  the 
lower  part  of  the  stomach,  in  the  back  of  the  abdomen, 
one  on  each  side  of  the  spinal  column.  In  a  grown  person 
they  are  about  four  inches  long  and  an  inch  and  a  half  wide. 
The  colored  picture  facing  page  110  shows  that  their  shape 
is  much  like  that  of  the  kidney  bean  which  was  named 
from  them.  The  blood,  from  which  it  is  their  duty  to 
extract  the  urea  and  some  other  wastes,  is  brought  to 
them  by  a  large  artery,  and  carried  away  by  a  large  vein. 
The  capillaries  of  the  kidneys  are  very  numerous  and 
they  are  so  arranged  that  the  thousands  of  small  tubes, 
called  kidney  tubes,  have  every  opportunity  to  take  out 


REMOVAL  OF  BODY  WASTES  231 

from  the  blood  the  water  and  the  urea  that  should  be 
removed.  This  is  collected  into  a  much  larger  tube,  called 
the  ureter,  which  carries  it  to  the  bladder  from  which 
the  waste  is  voided. 

The  kidneys  are 'at  work  continuously;  they  usually 
have  more  liquid  to  excrete  in  the  winter  months  than  in 
summer  when  one  perspires  freely,  but  exercise,  or 
anything  else  that  stimulates  the  circulation  of  the 
blood,  will  also  increase  their  action. 

When  the  bladder  is  nearly  filled,  there  is  a  natural 
demand  for  emptying  it ;  and  it  is  really  much  more 
important  that  this  demand  should  be  met  than  that 
we  should  meet  the  appetite  for  food.  The  body  can  get 
along  without  food  for  several  days  and  suffer  no  harm, 
but  if  the  poisons  that  are  gathered  in  the  bladder  are 
not  allowed  to  pass  off,  they  will  rapidly  injure  the 
bladder  and  soon  poison  the  whole  system. 

Kidney  Diseases.  —  Many  remedies  for  kidney  diseases 
are  advertised,  and  lurid  accounts  of  the  symptoms  of 
kidney  trouble  are  often  printed ;  but  sensible  people 
pay  no  attention  to  such  efforts  to  get  money  from  the 
ignorant.  When  the  kidneys  are  really  diseased,  the 
attention  of  a  good  physician  is  required,  not  some  dose 
of  patent  medicine. 

The  two  most  serious  diseases  which  result  in  abnormal 
kidney  excretions  are  called  diabetes  and  Bright's  disease. 
In  diabetes  sugar  is  excreted  by  the  kidneys ;  and  in  the 
most  common  form  of  the  disease  this  is  due  to  the  failure 
of  the  tissues  of  the  body  to  make  use  of  the  normal 
amount  of  sugar  as  a  fuel  food.  Muscular  weakness 
is  one  of  the  results,  because  the  muscles  are  not  getting 


232  PHYSIOLOGY   AND   HEALTH 

enough  fuel  food.     The  cause  of  this  form  of  the  disease 
is  not  fully  known. 

In  Bright' s  disease  the  kidneys  excrete  albumen,  which 
under  normal  conditions  would  be  used  for  the  repair  of 
the  body  and  as  fuel.  It  is  one  of  the  ways  in  which  a 
general  breakdown  of  the  body  mechanism  shows  itself. 
These  diseases  are  becoming  more  and  more  prevalent, 
hence  we  all  ought  to  take  pains  to  use  the  best  preven- 
tives against  them.  The  most  important  are  simply 
drinking  plenty  of  water  and  not  overeating ;  the  others 
are  the  maintenance  of  the  whole  system  in  healthy, 
vigorous  condition. 

QUESTIONS 

1.  Which  will  cause  death  more  quickly,  going  without  food  or 
allowing  the  poisons  of  the  body  to  accumulate? 

2.  Name  the  chief  poisons  that  are  produced  in  the  body.     How 
has  nature  provided  for  ridding  the  body  of  each  ? 

3.  Where  are  the  kidneys?    What  do  they  look  like?    How  im- 
portant to  the  health  of  the  body  is  the  work  of  the  kidneys  ? 

4.  Describe  how  the  kidneys  perform  their  work. 

5.  Do  you  think  an  insurance  company  would  be  likely  to  insure 
a  man  who  had  any  disease  of  the  kidneys  ? 

6.  How  do  the  liver  and  kidneys  work  together? 

7.  What  health  rules  should  one  be  sure  to  obey  if  he  would  keep 
the  organs  for  the  removal  of  wastes  in  a  healthy  condition  ? 

8.  Would  you  expect  a  man  who  eats  heavily  of  rich  food,  generally 
drinks  beer  with  his  meals,  and  is  carried  to  and  from  his  place  of 
business  in  a  limousine,  to  be  strong  and  well?    Why?     In  what  ways 
would  you  consider  his  chauffeur  as  more  fortunate  than  he  ? 


CHAPTER  XI 
STRUCTURE   AND   FUNCTIONS   OF   THE   SKIN 

Structure  of  the  Skin. --The  skin  covers  the  entire 
body  like  a  garment,  fitting  loosely  in  some  places,  as 
on  the  back  of  the  hands,  and  fitting  tightly  in  others, 
as  on  the  palm  of  the  hands.  A  grown  person  has  about 
sixteen  square  feet  of  skin. 

What  we  are  accustomed  to  call  the  skin  is  only  its 
outer  layer.  Looked  at  through  a  microscope,  a  cross 
section  of  skin  shows  two  layers  (Figure  75).  The 
outer  layer  is  called  the  epidermis.  The  inner  layer  is 
called  the  dermis ;  this  is  the  more  interesting  one,  for 
it  is  all  alive  and  is  full  of  nerves  and  blood  vessels.  The 
epidermis,  except  for  a  thin  layer  on  the  inner  side,  is 
practically  lifeless  and  contains  no  nerves  and  no  blood 
vessels.  It  is  easy  to  test  the  thickness  of  the  epidermis 
by  pricking  the  flesh  with  a  pin.  At  first  you  feel  no  pain 
because  the  pin  is  going  through  the  lifeless  epidermis; 
the  pain  begins  when  the  point  reaches  the  dermis. 

Outer  and  Inner  Skin.  —  Lifeless  things  do  not  grow, 
and  the  lifeless  outer  surface  of  the  epidermis  shows  no 
growth ;  yet  the  outer  skin  is  growing  all  the  time  on  its 
inner  surface  which  is  alive  and  in  contact  with  the  dermis. 
The  outer  and  inner  skin  are  so  firmly  attached  that  they 
are  not  easily  separated,  and  this  is  a  great  protection 
to  the  tender  inner  skin.  We  realize  how  tender  is  this 

233 


234 


PHYSIOLOGY   AND   HEALTH 


inner  skin  when  a  blister  breaks  and  the  outer  skin  peels 
off.  Small  blisters  should  be  carefully  opened  by  prick- 
ing the  skin  at  one  side  of  the  blister.  That  gives  relief 

by  letting  out   the  watery 
matter    that     has    formed, 
•|   and  it  leaves  the  outer  skin 
is   over  the  blister  to  protect 
w   the  deeper  cells. 

Figure  75  shows  that  the 
dermis  is  much  thicker  than 
the  epidermis,  and  consists 
of  a  mass  of  fibers,  running 
in  every  direction.  On  the 
side  next  to  the  epidermis 
the  fibers  are  packed  close 
|  together,  while  below  they 
Q  are  less  dense.  Between  the 
fibers  lie  tiny  fat  cells,  and 
throughout  are  many  blood 
vessels  and  many  nerves ; 
hence  the  dermis  always 
bleeds  when  cut  and  is  very 
sensitive. 

Hair. — The  epidermis  has 
several  outgrowths  which  do 
not  in  the  least  resemble  it ;  one  of  these  is  the  hair.  Each 
hair  extends  into  a  little  pocket  of  its  own,  called  the  hair 
follicle.  At  the  bottom  of  each  pocket  is  a  very  small 
mound,  or  papilla,  which  may  be  called  the  root  of  the  hair. 
The  hair  is  constantly  growing  at  its  root,  and  as  it  grows 
it  is  pushed  out  of  the  pocket.  When  a  hair  is  pulled  out, 


FIG.  75.  —  SECTION  OF  THE  HUMAN 
SKIN. 


STRUCTURE  AND   FUNCTIONS  OF  THE   SKIN     235 


--0/7  Gland 


..-Hair 


there  is  usually  no  injury  to  the  papilla,  which  proceeds  to 
grow  a  new  hair.  But  if  the  whole  follicle,  including  the 
papilla,  is  destroyed,  no  new  hair  will  grow. 

Each  hair  is  supplied  with  oil  from  one  or  more  tiny 
glands  that  open  into  the  follicle  from  the  sides,  as  shown 
in  Figure  76.  The 
oily  substance  they 
produce  distributes 
itself  over  the  sur- 
face of  the  hair  and 
keeps  it  soft  and 
flexible.  Being  life- 
less, the  hair  is  not 
connected  with  the 
nerves,  and  there  is 
no  sensation  in  it. 
When  an  inch  of  a 
girl's  braid  is  cut  off, 
she  only  knows  that 
it  is. gone  when  she 
hears  the  scissors 
cut  or  sees  the  bit  of 
hair.  There  is  hair 
on  nearly  all  parts  of 
the  body  excepting  the  palms  of  the  hands  and  the  soles 
of  the  feet.  In  places  where  it  just  barely  reaches  the 
surface  we  often  do  not  notice  it. 

The  Nails.  —  Other  outgrowths  of  the  epidermis  are 
the  finger  nails  and  the  toe-nails ;  they  are  of  a  horny 
substance,  and  like  the  hair  are  lifeless  and  have  no  feeling. 
Pressing  too  hard  on  a  finger  nail  does  not  cause  pain  in  the 


-Bulb 


-Fat 


FIG.  76.  —  SECTION  OF  THE  HUMAN  SKIN,  SHOW- 
ING Two  HAIRS. 


236 


PHYSIOLOGY   AND   HEALTH 


nail,  but  in  the  delicate  skin  that  lies  under  it.  Pulling 
the  nail  hurts,  while  cutting  it  does  not,  because  the  pull 
is  felt  by  the  nerves  in  the  finger  where  the  nail  is  attached. 
The  nail  is  continually  growing  outward  from  the  root. 
When  injured  seriously,  a  nail  will  come  off,  but  a  new 
one  grows  again  unless  the  root  has  been  badly  injured. 
The  half  moon  near  the  root  of  the  nails  is  of  the  same 
substance  as  the  rest  of  the  nail ;  the  difference  in  ap- 
pearance is  due  to 
the  fact  that  at 
this  point  the 
nail  is  new  and 
thin  and  under- 
neath it  there 
are  fewer  blood 
vessels. 

Sweat  Glands 
and  Pores. — 
Sweat,  as  a  means 

FIG.  77.  —  A  BIT  OF  THE  HUMAN  SKIN.  of      Carrying      off 

Showing  the  sweat  glands  and  pores  and  the  differ-     SOme  of  the  body 


waste,     has     al- 


ent  layers  of  the  skin. 

ready  been  discussed.  We  can  readily  see  the  sweat 
drops,  but  the  sweat  glands  that  produce  them  are  too 
small  for  us  to  see.  There  are  some  two  and  a  half  mil- 
lions of  them  in  the  skin.  They  start  in  the  dermis  as 
coiled  tubes ;  the  tubes  pass  up  through  the  dermis  and 
the  epidermis,  and  open  at  the  surface  in  what  are  called 
pores.  There  are  as  many  pores  as  there  are  sweat 
glands,  and  through  them  the  sweat  comes  to  the  outer 
part  of  the  skin  (Figure  77).  The  skin  of  the  whole 


STRUCTURE   AND   FUNCTIONS  OF  THE  SKIN     237 


body  is  covered  with  these  tiny  pores ;  they  are  most 
numerous  upon  the  forehead,  the  palms  of  the  hands, 
and  the  soles  of  the  feet. 

The  skin  of  the  fingers  is  covered  with  irregular  furrows ; 
and  the  pattern  of  those  furrows  is  different  with  every 
person.     The  thumb  print   shown  in  Figure   78  is  that 
of  the  author  of  this  book,  and  no  one 
else  in  the  world  has  one  like  it.     Since 
no   two   persons   have   the  same  mark- 
ings on  their  fingers,  these  finger  prints 
are  a  far   surer  method   of  recognizing 
a   person   than   his   photograph ;    hence 
their  use   by  the   police  to   detect  and 
recognize    criminals.     The   pores  lie   on 
the    ridges    between    these    furrows,    as 
seen  in  Figure   77 ;   even  a  small  mag- 
nifying glass  will  show  them. 


FIG.  78.  — A  THUMB 
PRINT. 


Functions  of  the  Skin 


The  complicated  structure  of  the  skin  and  the  number 
of  its  accessory  pa*ts  show  that  it  is  designed  to  serve 
many  different  purposes.  Its  use  as  an  organ  of  excretion 
has  already  been  described  ;  it  has  three  other  important 
functions  which  are  so  nicely  adjusted  to  one  another 
that  they  all  go  on  at  the  same  time  without  the  least 
conflict  or  interference.  The  skin  gives  protection  to 
the  body  without  losing  any  of  the  sensitiveness  required 
in  an  organ  of  sense;  and  it  uses  the  same  sweat  glands  for 
eliminating  waste  and  for  the  much  more  important  pur- 
pose of  regulating  body  temperature. 

1.   As  a  Protection.  —  The  flat,  scale-like  cells  of  the 


238  PHYSIOLOGY  AND  HEALTH 

outer  skin,  packed  close  together,  many  layers  deep,  give 
great  protection  to  the  flesh  beneath.  The  cheinist  can 
plunge  his  hand  into  many  poisonous  liquids  without 
danger,  because  the  poisons  cannot  get  through  the  cells 
of  the  epidermis.  In  the  same  way  this  outer  guard  of 
our  bodies  prevents  dangerous  disease  germs  from  getting 
into  them.  Some  of  these  various  germs  are  always  on 
our  skin  and  our  clothing,  and  if  they  can  get  into  the 
body,  they  will  grow  there  and  produce  trouble. 

2.  As  a  Sense  Organ.  —  When  sense  organs  are  men- 
tioned one  thinks  of  the  eyes,  the  ears,  the  nose,  and  the 
tongue;   but  the  sense  of  touch,  which  is  located  in  the 
skin,  makes  it  one  of  the  most  important  of  the  sense 
organs.     In  the  skin  too  is  our  sense  of  temperature,  for 
it  is  chiefly  through  the  skin  that  we  feel  heat  and  cold. 
Some  of  the  tiny  microscopic  organs  in  the  skin  are,  as 
we  have  seen,  affected  by  heat  and  cold,  and  there  are 
others   that   are   affected   by   pressure;     each   responds 
quickly  to  its  own  stimulus,  and,  through  the  messages  they 
send,  the  brain  is  constantly  being  given  information 
about  what  is  touching  the  skin. 

3.  As  a  Regulator  of  Body  Temperature.  —  All  parts 
of  the  body  have  to  be  kept  at  a  comparatively  even 
temperature,    or    else    we    become    ill.     Sometimes    our 
bodies  make  too  much  heat  and  at  other  times  too  little. 
If  we  exercise  vigorously,  the  muscles  produce  so  much 
heat  that  the  body  would  be  too  warm  if  it  could  not  get 
rid  of  its  excess  heat.     The  maintaining  of  the  proper 
temperature  rests  upon  the  sweat  glands  of.  the  skin  and 
its  blood  vessels. 

It  may  be  easier  to  understand  how  they  accomplish 


STRUCTURE   AND   FUNCTIONS  OF  THE  SKIN     239 

their  task  if  we  consider  the  means  by  which  the  heat  of 
a  room  is  regulated.  We  know  that  the  amount  of  heat 
admitted,  to  a  schoolroom  for  instance,  must  be  rightly 
proportioned  to  the  amount  of  cold  air  admitted;  in  the 
winter  it  is  necessary  to  be  alternately  opening  the  hot- 
air  registers  and  closing  the  windows  or  vice  versa.  The 
body  uses  similar  measures,  only  under  ordinary  con- 
ditions the  body's  temperature  depends  more  upon  the 
opening  and  closing  of  its  windows  (i.e.  the  increasing  or 
checking  of  skin  circulation)  than  upon  checking  or 
increasing  the  amount  of  heat  produced. 

Heat  Production.  -  -  The  heat  manufactured  in  the 
body  cannot  be  governed  wholly  by  the  question  of 
the  amount  needed  to  maintain  an  even  body  tempera- 
ture. The  muscles  must  keep  working,  and  when  they 
work,  heat  is  produced  even  though  the  day  is  warm 
and  the  body  happens  for  that  reason  not  to  need  the 
heat.  In  this  respect  the  body  might  be  compared  to  a 
kitchen  range  whoso  heat  must  be  kept  up  even  on  a 
hot  day  in  order  to  do  the  cooking.  To  make  the  kitchen 
comfortable  to  work  in,  the  windows  must  be  opened  to 
help  cool  the  air.  The  heat  made  in  the  body  is  deter- 
mined by  the  body's  activities;  when  they  result  in 
more  heat  than  the  body  needs,  the  regulating  apparatus 
has  to  work  hard  in  order  to  get  rid  of  the  extra  heat. 

Heat  Regulation.  —  The  regulating  process  is  simply 
this :  The  temperature  of  the  skin  is  about  95°,  which  is 
always  lower  than  that  of  the  interior  of  the  body  and 
is  usually  higher  than  that  of  the  air  with  which  the  skin 
comes  in  contact.  So  the  warm  blood  that  fills  the  many 
small  blood  vessels  of  the  skin  is  constantly  being  cooled 


240  PHYSIOLOGY  AND   HEALTH 

by  the  air ;  the  faster  the  blood  flows  through  the  skin, 
the  more  it  is  cooled.  When  there  is  too  much  heat, 
the  blood  vessels  of  the  skin  expand,  more  blood  flows 
into  them,  more  heat  is  lost,  and  the  body  is  cooled.  This 
does  not  mean  that  we  feel  cooler.  We  may  actually  feel 
warmer  because  of  the  amount  of  warm  blood  flowing 
through  the  skin ;  but,  however  we  may  feel,  the  fact  is 
that  the  body  is  relieved  of  its  excess  heat. 

When  the  body  is  making  too  little  heat,  the  blood 
vessels  in  the  skin  contract  until  their  tubes  are  very  small 
and  hence  will  let  only  a  little  blood  through  the  skin. 
By  checking  the  heat  outlet  from  the  skin  the  heat  is 
kept  within  the  body.  At  the  same  time  the  skin  be- 
comes pale  and  the  person  is  likely  to  feel  cold ;  this 
feeling  of  cold  is  not  due  to  a  drop  in  the  temperature  of 
the  body,  which  is  being  carefully  kept  at  98.6°,  but  to 
the  tiny  organs  in  the  skin  that  feel  heat  and  cold.  When 
there  is  less  warm  blood  flowing  around  them,  they  send 
a  cold  report  to  the  brain.  On  a  hot  day,  or  whenever 
much  blood  is  sent  to  the  skin,  the  same  little  organs  re- 
port heat,  though  the  actual  temperature  of  the  body 
is  no  higher  than  it  was  on  the  day  when  they  reported 
cold.  The  temperature  reports  that  the  brain  gets 
from  the  skin  are  of  skin  temperatures  only.  The  brain 
receives  few  other  temperature  reports  except  from  the 
lining  of  the  mouth  and  of  the  digestive  tract. 

The  lungs  also  help  to  dispose  of  excess  heat.  The 
air  drawn  into  them  is  usually  much  cooler  than  is  the 
blood  as  it  comes  to  the  lungs.  Thus  the  blood  lowers 
its  own  temperature  by  giving  up  some  of  its  heat  to  the 
air. 


STRUCTURE  AND   FUNCTIONS  OF  THE  SKIN     241 

Heat  and  Animal  Activity.  —  Emphasis  is  laid  on  the 
means  provided  for  disposing  of  excess  heat  because  in 
the  case  of  man  and  of  all  active  animals  the  activities 
of  life,  especially  the  working  of  the  muscles,  produce 
more  heat  than  the  body  needs  under  ordinary  conditions. 
When  a  boy  is  riding  a  bicycle  rapidly,  he  is  probably 
producing  four  to  six  times  as  much  heat  as  when  he  is 
asleep ;  so  there  must  be  thorough  and  prompt  provision 
for  taking  care  of  a  large  amount  of  extra  heat. 

It  is  equally  necessary  that  sufficient  fuel  food  to  pro- 
duce heat  should  be  taken  by  man  and  all  the  active 
animals  (called  warm-blooded  animals).  If  there  is 
shortage  of  such  food,  the  body  may  use  its  stored-up 
fat  for  a  short  time ;  after  that  the  body  heat  must  begin 
to  drop  and  death  will  soon  follow.  When  we  say  that 
a  man  or  an  animal  died  from  "  starvation/7  it  usually 
means  that  death  came  because  the  body  temperature 
could  no  longer  be  maintained.  Lack  of  food  does  not  so 
quickly  produce  trouble  if  one  has  warm  clothing,  for 
with  warm  clothing  the  heat  of  the  body  can  be  more 
easily  maintained. 

Inactive  and  Hibernating  Animals.  —  Animals  like 
frogs  and  snakes  need  much  less  food  than  others,  be- 
cause they  do  not  use  it  to  maintain  their  body  tempera- 
ture; their  bodies  are  not  kept  warmer  than  the  air 
about  them.  On  a  cold  day  their  bodies  are  cold,  on  a 
hot  day  they  are  hot.  These  animals  will  usually  be  more 
active  on  a  warm  day,  but  all  their  vital  processes  go  on 
properly  no  matter  what  their  temperature  is.  They 
are  called  cold-blooded  animals  because  they  usually  feel 
cold  when  we  touch  them,  since  our  bodies  are  always 


242  PHYSIOLOGY   AND   HEALTH 

about  98°,  which  is  warmer  than  these  animals  are  during 
the  greater  part  of  the  year. 

Bears  and  some  other  warm-blooded  animals  have  a 
peculiar  way  of  meeting  the  difficulty  of  getting  sufficient 
food  during  the  winter.  When  winter  comes,  they  go  to 
sleep  in  then*  dens  and  often  stay  there  until  spring. 
During  this  long  time  without  food  the  body  temperature 
falls  quite  low,  but  it  does  them  no  harm,  for  they  are 
able  when  they  wake  to  restore  quickly  the  normal 
heat  of  the  body  by  burning  the  excess  fat  that  was 
stored  up  in  the  fall  for  that  purpose.  They  are  called 
hibernating  (wintering)  animals  because  of  their  peculiar 
way  of  getting  through  the  winter  season. 

Cooling  by  Evaporation.  —  There  are  two  conditions 
under  which  a  man  perspires  freely  —  on  a  hot  day,  and 
when  he  is  doing  hard  muscular  work.  In  both  these 
cases  much  more  heat  is  being  made  than  the  body  needs, 
and  profuse  perspiration  starts ;  it  may  even  stand  out 
in  drops.  If  nothing  else  happened,  the  body  would  not 
be  cooled.  It  is  the  evaporation  of  the  sweat  that  causes 
the  lessening  of  the  temperature.  The  evaporation  of 
water  requires  much  heat;  hence  as  the  water  on  the 
skin  is  evaporated  by  the  heat  of  the  blood  circulating 
through  the  skin  the  blood  loses  a  considerable  quantity 
of  heat  and  the  body  becomes  cooler.  It  is  estimated 
that  by  means  of  perspiration  alone  the  body  is  able  to 
get  rid  of  three  times  as  much  heat  as  it  requires. 

Keeping  the  air  stirring  greatly  aids  evaporation.  On 
a  very  hot  day  we  are  much  more  comfortable  if  the  wind 
is  blowing,  because  evaporation  is  then  more  rapid.  A 
hot,  "  muggy  "  day  is  even  more  uncomfortable  than  a. 


STRUCTURE  AND   FUNCTIONS  OF  THE   SKIN     243 

hot,  breezeless  day,  for  the  moisture  in  the  muggy  air 
delays  evaporation. 

Importance  of  the  Sweat  Glands.  —  Were  it  not  for 
the  sweat  glands  we  should  have  to  make  great  changes 
in  our  habits  of  life  as  soon  as  the  hot  weather  came.  If 
we  did  not  perspire  then,  we  could  not  work  because  the 
other  two  methods  of  .cooling  the  blood  could  not  cool 
it  sufficiently,  if  unaided.  This  was  demonstrated  in  the 
case  of  a  man,  born  with  an  imperfect  skin,  who  had  no 
sweat  glands.  This  man  was  not  able  to  do  any  work  in 
hot  weather,  for  as  soon  as  he  exerted  himself  his  tem- 
perature began  to  go  up,  and  he  was  soon  in  a  state  of 
"  fever,"  and  became  really  ill  if  he  kept  on  trying  to 
work.  His  body  could  not  give  off  enough  heat  through 
the  lungs,  or  by  sending  the  blood  rapidly  to  the  skin,  to 
keep  his  temperature  normal,  and  having  no  sweat  glands, 
he  could  not  perspire. 

Notice  the  difference  between  horses  and  dogs  in  hot 
weather :  the  horse  perspires  freely,  the  dog  has  fewer 
sweat  glands  and  has  to  cool  his  blood  by  rapid  breathing, 
panting.  Some  people  perspire  freely,  some  do  not ; 
other  things  being  equal,  the  more  freely  a  man  perspires 
the  less  he  feels  the  heat.  Some  men  cannot  for  that 
reason  work  as  stokers ;  they  do  not  perspire  enough  to 
enable  them  to  endure  the  great  heat  of  the  place  where 
their  work  must  be  done. 

Life  at  Heat  above  Boiling.  —  There  is  an  excellent 
illustration,  more  than  a  hundred  years  old,  of  the 
ability  of  the  body  to  keep  its  proper  temperature  in 
the  midst  of  great  heat.  Some  adventurous  scientists 
tried  to  determine  by  experimenting  on  themselves  the 


244.  PHYSIOLOGY   AND   HEALTH 

effect  of  very  high  temperatures.  They  finally  went  into 
a  room  where  the  thermometer  stood  at  260°,  which  is 
48°  hotter  than  the  temperature  at  which  water  boils. 
The  heat  was  certainly  great  enough  to  burn  their  skin 
(and  that  is  what  might  have  happened  to  the  man  who 
had  no  sweat  glands),  but  they  were  able  to  remain  there 
for  some  time.  The  air  they  were  breathing  was  hot 
enough  to  cook  in  twenty  minutes  the  raw  meat  and  eggs 
they  took  into  the  room,  and  the  metal  buttons  on  their 
clothing  became  so  hot  as  to  burn  their  fingers.  In  that 
temperature  the  men  were  very  uncomfortable,  it  is 
true,  but  the  prompt  and  profuse  action  of  their  two 
and  a  half  million  sweat  glands  made  it  possible  for  them 
to  come  out  of  the  room  uninjured ;  and  it  is  highly 
probable  that  if  use  were  made  of  all  modern  appliances  for 
keeping  air  in  constant  motion,  and  so  hastening  evapora- 
tion, even  greater  heat  could  be  borne  for  a  short  time. 

Although  heat  is  the  usual  cause  of  perspiration,  it 
may  start  because  of  some  sudden  emotion,  of  fear,  or  of 
embarrassment ;  pain  also  may  have  the  same  effect. 

Deceptive  Temperature  Regulators.  —  No  matter  how 
warm  we  may  feel,  we  are  actually  losing  heat  whenever 
the  blood  vessels  in  the  skin  are  opened  wider  than 
usual.  When  certain  substances,  like  alcohol,  are  taken 
into  the  stomach,  the  blood  vessels  enlarge,  the  skin 
becomes  flushed,  and  the  body  feels  warm.  Some  people 
actually  take  alcohol  on  a  cold  day  to  keep  them  warm. 
They  are  being  deceived  by  their  feelings,  for  it  does  not 
and  cannot  warm  them.  The  person  feels  warmer  be- 
cause the  skin  is  heated,  but  in  fact  he  really  is  losing 
body  heat  more  rapidly  than  before. 


STRUCTURE  AND   FUNCTIONS  OF  THE  SKIN     245 

Many  instances  might  be  given.  One  striking  experi- 
ence is  that  of  a  party  of  travelers  who  were  obliged  to 
spend  the  night  upon  an  exposed  place  in  the  mountains. 
The  cold  was  intense,  and  they  had  little  protection  from  it. 
Some  of  them  took  alcoholic  drinks  to  prepare  themselves, 
as  they  supposed,  to  endure  the  cold,  while  others  did  not. 
Those  who  drank  soon  felt  warmer  because  their  warm 
blood  began  to  flow  through  the  skin,  but  before  morning 
all  those  who  had  taken  the  alcohol  had  died  from  the 
exposure.  Those  who  did  not  drink  the  alcohol  suffered 
more  from  the  cold,  at  first,  because  the  warm  blood  was 
kept  within  their  bodies,  but  they  were  able  to  endure 
the  experience  and  were  none  the  worse  for  it. 

Men  who  go  to  the  far  north,  on  whaling  expeditions 
or  for  exploration,  used  to  suppose  that  alcohol  was 
needed  to  help  meet  such  exposure.  Then  science 
discovered  the  way  alcohol  acts,  and  that  the  warmth  it 
seems  to  give  is  not  real  but  deceptive.  So  explorers  have 
learned  the  lesson,  and  now  those  whose  lives  depend 
for  months  at  a  time  upon  their  being  in  condition  to  do 
much  hard  work,  and  to  stand  all  kinds  of  exposure, 
seldom  risk  the  use  of  alcohol. 


QUESTIONS 

1.  What  happens  when  a  blister  forms?    Why  is  the  skin  under  a 
broken  blister  so  sensitive? 

2.  In  what  part  of   the  body  is   the   skin  thickest?    Why?     In 
what  parts  is  it  most  loosely  attached  to  the  underlying  muscles  ?     Most 
closely  attached  ? 

3.  What  happens  to  the  skin  when  we  exercise  vigorously  ?    Where 
do  we  feel  warm? 


246  PHYSIOLOGY   AND   HEALTH 

4.  What  would  happen  if  all  the  sweat  glands  of  the  body  were 
closed  ? 

5.  How  much  warmer  is  a  healthy  body  in  summer  than  in  winter  ? 
Why  do  we  sweat  more  in  summer  ?    What  effect  does  this  have  on  the 
body  temperature?     Why  does  a  dog  "pant"  in  warm  weather? 

6.  What  is  it  that  makes  wounds  and  serious  burns  so  dangerous? 

7.  How  do  we  know  when  the  air  is  warm?    Why' does  a  nurse 
test  the  temperature  of  water  with  her  elbow  instead  of  using  her 
hand?    Why  does  a  woodsman  moisten  his  finger  and  hold  it  up  to 
know  which  way  the  wind  blows  ? 

8.  Why  do  we  feel  cooler  on  a  windy  day  than  on  a  still  day  even 
when  the  temperature  is  the  same?     \ 

9.  If  the  skin  did  not  regulate  the  temperature  of  the  body,  what 
would  happen  when  the  weather  changed  suddenly  ?    Why  do  we  wear 
more  clothing  in  winter  than  in  summer?    Why  do  we  need  more 
when  sleeping? 

10.  What  happens  to  the  temperature  of  the  body  when  a  person 
has  a  fever?    How  does  the  doctor  "take  the  temperature"?    Why 
does  he  not  test  it  by  placing  the  thermometer  against  the  hand  or 
cheeks  ? 

11.  Why  should  we  avoid  drafts  when  we  are  overheated?    How 
may  we  get  cooled  off  without  danger  of  cold? 

12.  Why  does  a  boy  riding  a  bicycle  feel  cool  while  moving  and 
warm  when  he  stops  ? 

13.  What  is  the  difference  between  warm-blooded  and  cold-blooded 
animals  ?    Name  examples  of  each  class. 

14.  What  relation  does  our  food  have  to  the  temperature  of  the 
body? 

15.  Place  the  back  of  your  hand  on  a  cold  windowpane  and  then 
the  front  of  the  hand.     In  which  case  does  more  moisture  collect? 
Why? 

16.  An  expressman,  on  a  cold  day,  was  invited  into  a  house  to  get 
warm.     "No,"  he  replied,  swinging  his  arms,  "it  is  better  for  me  to 
get  warm  this  way."     Give  the  reasons  for  his  answer. 

17.  Why  does  one  feel  the  cold  more  when  going  out  immediately 
after  eating?    Is  his  body  temperature  lower? 


CHAPTER  XII 
TAKING  CARE  OF  THE  SKIN 

MANY  boys  and  girls  regard  the  f  daily  bath,  which  is 
demanded  by  consideration  for  themselves  and  others, 
as  an  unmitigated  nuisance.  On  the  other  hand,  ex- 
perience has  taught  army  commanders  that  bathing  is 
one  of  the  best  protections  against  disease,  and  that  a 
clean  skin  is  a  safeguard  against  infection  from  wounds. 
Laziness  and  scrupulous  cleanliness  must  have  many  a 
combat  before  a  young  person's  habits  are  fully  formed ; 
but  the  daily  bath  surely  ought  to  win  the  conflict  since 
its  advantages  are  so  many  and  so  obvious. 

Why  We  Bathe.  —  1.  The  skin  is  cleaned.  The  waste 
matter  that  the  body  gives  off  through  the  skin  has  an 
offensive  odor,  and  if  allowed  to  remain  on  the  skin,  the  odor 
of  the  body  will  become  perceptible  and  unpleasant  to  those 
around  us,  though  we  ourselves  are  unconscious  of  it. 
Surely  no  one  wishes  his  body  to  be  unpleasant  to  his 
friends,  and  the  best  way  to  prevent  that  is  to  remove 
the  waste  material  by  frequent  bathing,  which  leaves  the 
skin  sweet  and  clean.  If  for  any  reason  a  daily  bath  is 
not  feasible,  a  hard  rubbing  of  the  skin  with  a  coarse 
towel  will  remove  much  of  the  waste  matter  and  may 
answer  as  an  occasional  substitute  for  the  bath. 

2.  The  skin  is  stimulated.  In  the  skin  there  are 

247 


248  PHYSIOLOGY   AND   HEALTH 

thousands  of  tiny  muscles  that  control  the  small  blood 
vessels ;  these  muscles  should  get  their  stimulus  to 
action  from  the  contact  of  the  skin  with  cold  air  and 
hot  air.  In  cold  weather  all  the  skin,  except  that  of  the 
hands  and  the  face,  is  generally  covered  with  clothing. 
As  a  result  it  is  constantly  kept  so  warm  that  these 
muscles  fail  to  get  their  proper  exercise,  and  so  they 
become  sluggish  as  any  other  muscles  would.  A  bath 
gives  these  muscles  the  exercise  they  need,  and  for  this 
purpose  a  cold  bath  is  more  effective  than  a  hot  one. 
However,  if  a  hot  bath  is  followed  by  rubbing  the  body 
with  a  towel  wrung  out  of  cold  water  (when  a  cold  shower 
cannot  be  taken),  the  effect  is  good. 

3.  It  is  a  protection  against  colds.  The  daily  cold 
bath  is  almost  a  sure  protection  against  colds.  The  skin 
learns  to  adapt  itself  readily  to  sudden  changes  in  tem- 
perature that  might  otherwise  cause  a  congestion  of  the 
air  passages  and  thus  give  the  germs  there  every  op- 
portunity to  produce  a  cold  or  some  more  serious  ailment. 
Putting  cold  water  on  the  face,  neck,  and  shoulders 
every  morning  helps  to  fortify  the  organs  which  are 
usually  attacked  by  a  cold. 

Cold  Baths.  —  A  vigorous  person  gets  real  exhilaration 
from  a  cold  bath:  some  can  take  a  cold  plunge  every 
morning  and  feel  better  for  it  all  day ;  others  thrive  better 
when  they  take  a  cold  shower  bath ;  others  find  that  a 
cold  sponge  bath  suits  them  better.  Every  one  takes  the 
beginning  of  a  cold  sponge  when  he  washes  his  face  in 
cold  water,  and  cold  water  ought  always  to  be  put  on  to 
the  face  because  it  is  so  much  better  for  the  complexion. 
Those  who  are  not  used  to  taking  cold  baths  would  do 


TAKING   CARE   OF  THE  SKIN  249 

well  to  begin  them  gradually.  Day  by  day  a  larger  sur- 
face of  the  body  may  be  treated  to  the  cold  sponge ;  then 
when  the  body  is  accustomed  to  the  effect  of  cold  water, 
a  cold  shower  or  plunge  may  be  tried. 

In  a  cold  bath,  the  first  sensation  is  one  of  cold,  and 
the  result  is  that  the  blood  vessels  of  the  skin  contract, 
leaving  the  skin  white  and  cold.  Soon  comes  what  is 
called  the  reaction;  the  blood  vessels  open  and  allow  the 
warm  blood  from  the  interior  to  flow  rapidly  through  the 
skin.  There  is  a  feeling  of  exhilaration,  and  the  skin 
becomes  flushed  and  warm.  Before  this  glow  passes, 
one  should  leave  the  water,  for  if  he  stays  longer,  he 
becomes  chilly  again,  and  may  remain  cold  and  uncom- 
fortable for  hours.  One  must  determine  the  time  by  ex- 
perience, for  much  depends  upon  the  person,  the  tempera- 
ture, and  the  water ;  the  glow  lasts  longer  after  a  bath 
in  salt  water.  Vigorous  friction  of  the  body  with  a  rough 
towel  after  the  bath  will  increase  the  glow  and  the  benefit 
derived. 

Hot  Baths.  —  From  the  ordinary  hot  bath  the  body 
gets  none  of  the  good  effects  that  come  from  a  cold 
bath ;  the  muscles  attached  to  the  blood  vessels  get  little 
exercise  and  there  is  no  exhilarating  reaction.  A  hot 
bath  is  beneficial,  however,  whenever  it  is  desirable  to 
call  the  blood  to  the  surface  of  the  body.  If  one  is  rest- 
less and  wakeful  at  bedtime,  a  hot  bath  will  draw  the 
blood  from  the  brain ;  if  one  has  symptoms  of  a  cold, 
a  hot  bath  may  draw  the  blood  from  the  throat  and  nose 
sufficiently  to  prevent  the  cold  from  developing ;  in  case 
of  fatigue  a  very  hot  bath  relaxes  the  overstimulated 
parts  of  the  body.  An  occasional  hot  bath  is  also  de- 


250  PHYSIOLOGY   AND   HEALTH 

sirable  for  the  thorough  cleansing  of  the  body,  even 
when  a  cold  bath  is  taken  every  day. 

Cold  baths  are  stimulating  and  invigorating  and  are 
most  valuable  in  the  morning,  just  after  rising. 

Hot  baths  are  not  invigorating  and  should  generally  be 
taken  before  retiring  at  night. 

Tepid  baths  are  useful  for  cleansing  the  skin,  and  as 
they  have  no  other  effect  upon  the  body  they  may  be 
taken  at  any  time. 

Baths  for  Special  Purposes.  —  Various  kinds  of  baths 
are  sometimes  used  for  special  purposes.  In  a  steam 
bath  the  person  is  immersed  for  some  time  in  hot  steam, 
as  hot  as  he  can  bear  it.  Mud  baths  we  hear  of  occa- 
sionally, and  various  other  warm  substances  may  be  used 
to  give  different  types  of  thermal  (heat)  baths.  There 
is  a  modified  form  of  bath,  called  a  "  pack."  Here  the 
person,  or  a  part  of  his  body,  is  wrapped  closely  in  wet 
bandages,  sometimes  hot  and  sometimes  cold.  If  one 
is  kept  wrapped  up  in  this  way,  the  •"  pack  "  causes  the 
blood  vessels  of  the  skin  to  enlarge,  thus  relieving  internal 
congestion.  A  cold  "  pack  "  put  on  at  night  around  the 
neck  is  an  excellent  remedy  for  hoarseness  or  a  sore 
throat.  All  these  types  of  special  baths  are  used  chiefly 
for  persons  who  are  ill,  and  they  are  commonly  taken 
under  the  advice  of  a  physician. 

Care  in  the  Use  of  Towels.  —  Each  member  of  a 
family  should  have  and  use  his  own  towels.  Many 
cases  of  certain  diseases  of  the  skin  and  of  the  eyes  have 
been  traced  to  the  use  by  others  of  a  towel  that  has 
been  used  by  some  one  who  had  the  disease.  *  Nor  is  it 
sufficient  to  take  precautions  only  when  we  see  the  need 


TAKING  CARE   OF  THE  SKIN  251 

for  them,  as  when  we  are  with  a  person  who  has  some 
skin  eruption,  for  instance.  Germs  of  various  diseases 
may  pass,  as  we  have  learned,  from  one  well  person-  to 
another,  producing  disease  in  the  second  person  but  not 
in  the  first ;  so  individual  towels  and  other  toilet  articles 
are  important.  Even  greater  are  the  dangers  that  may 
lurk  unseen  in  a  towel  placed  in  a  public  building  or  con- 
veyance for  the  use  of  all  comers,  sick  and  well,  cleanly 
and  uncleanly. 

Care  of  the  Hair.  —  Frequent  brushing  of  the  hair  is 
not  only  necessary  to  a  tidy  and  pleasing  appearance, 
but  it  also  helps  to  keep  the  natural  oil  distributed  over 
the  hair.  A  soft  brush  and  a  rubber  or  bone  comb 
should  be  used;  wire  brushes  and  metal  combs  are  too 
harsh.  Nobody  would  think  of  using  a  public  tooth- 
brush. The  use  of  a  public  comb  or  hairbrush  is  almost 
as  dangerous.  Since  the  hair  is  frequently  exposed  to 
the  dust,  there  are  likely  to  be  disease  germs  on  it,  and 
there  are  also  special  diseases  of  the  scalp,  some  of 
them  highly  contagious,  that  are  easily  spread  through 
germs  left  on  comb  and  brush. 

Falling  Hair.  —  The  fact  that  the  hair  sometimes  falls 
out  is  well  known,  yet  little  is  actually  known  about  the 
cause  of  falling  hair  or  the  remedy  for  it.  Any  simple 
means  of  increasing  the  circulation  in  the  scalp,  like  pinch- 
ing or  rubbing  it  gently  with  the  fingers,  will  help  to  nour- 
ish and  strengthen  it.  Keeping  the  scalp  clean,  by  wash- 
ing it  once  or  twice  a  month  in  water  and  some  pure  soap, 
is  also  a  good  habit.  There  can  be  no  doubt  either  that 
"  toning  up  "  the  general  health  will  help  to  keep  the 
hair  growing  vigorously.  But  why  children's  hair  grows 


252  PHYSIOLOGY   AND   HEALTH 

thin,  at  times,  and  why  men  have  a  tendency  in  middle 
life  to  grow  bald  —  those  are  questions  which  cannot  be 
answered  with  any  certainty.  There  are  many  theories, 
but  none  of  them  has  proved  itself. 

Care  of  the  Nails.  —  Long  before  men  discovered  how 
many  disease  germs  might  lurk  in  the  dirt  beneath 
finger  nails,  fastidious  people  took  pains  to  keep  their 
nails  clean  and  shapely.  When  we  consider  how  many 
things  we  are  constantly  doing  with  our  hands  that 
affect  the  pleasure,  comfort,  or  health  of  other  people, 
we  can  see  that  they  have  a  right  to  expect  us  to  keep 
hands  and  nails  clean  and  tidy.  Dirt  should  be  re- 
moved from  under  the  nails  every  time  the  hands  are 
washed.  The  nails  should  be  trimmed  at  the  ends,  with 
scissors  or  file ;  neither  the  surface  of  the  nail  nor  the 
skin  covering  the  root  should  be  scraped. 

Some  children  form  the  bad  habit  of  biting  the  nails. 
This  is  likely  to  injure  the  shape  of  the  fingers,  besides 
being  disagreeable  to  others.  The  habit  can  be  over- 
come if  one  simply  makes  up  his  mind  to  control  it ;  the 
will  needs  exercise  to  strengthen  it  just  as  much  as  the 
muscles  do.  The  boy  or  girl  who  is  going  to  be  a  success 
in  life  must  be  able  to  do  hard  things  when  they  are 
required.  Breaking  bad  physical  habits,  like  this  one, 
gives  the  will  excellent  preparation  for  meeting  the  de- 
mands of  life. 

The  Choice  of  Clothing.  —  We  wear  clothing  (1)  for 
comfort  and  adornment ;  (2)  to  keep  in  the  body  heat, 
and  to  prevent  its  passing  off  too  rapidly  through  the 
skin.  For  comfort  in  winter,  it  is  necessary  to  cover 
the  body  with  heavy  clothing;  in  summer,  the  less 


TAKING   CARE   OF  THE  SKIN  253 

clothing  we  wear  the  more  comfortable  we  are.  Cloth- 
ing in  itself  does  not  warm  the  body,  but  different  kinds 
have  quite  different  effects  upon  the  body  heat.  Ma- 
terials that  carry  off  heat  rapidly  (called  "  good  con- 
ductors ")  will  cool  the  body  quickly,  while  materials 
that  conduct  heat  slowly  will  help  the  body  to  keep  warm. 

Linen  carries  heat  away  very  rapidly,  cotton  less 
rapidly,  while  woolen  is  the  poorest  conductor  of  heat. 
Hence  in  warm  weather,  when  we  want  to  reduce  the 
body  heat,  linen  and  cotton  are  the  best  materials  for 
clothing,  while  in  cold  weather,  when  we  want  to  retain 
the  heat  in  the  body,  woolen  clothing  should  be  worn. 
People  used  to  think  that  closely  woven,  firm  cloth  was 
the.  warmest,  but  it  has  been  discovered  that  the  air- 
filled  spaces  in  cloth  are  very  poor  conductors  of  heat ; 
so  clothing  made  of  coarsely  woven  cloth  is  really  the 
best  for  keeping  the  body  warm  in  cold  weather. 
Similarly,  two  light  garments,  worn  one  over  the  other, 
are  warmer  than  a  single  heavy  one  of  equal  weight,  for 
the  air  space  between  the  two  garments  acts  as  a  non- 
conductor of  heat. 

Many  people,  especially  those  who  do  not  take  a  cold 
bath  every  day,  complain  that  a  woolen  undergarment 
worn  next  the  skin  irritates  and  gives  much  discomfort. 
A  simple  remedy  is  to  wear  a  cotton  garment  next  to 
the  skin,  and  a  woolen  one  over  that.  For  people  who 
are  indoors  most  of  the  time  this  is  an  excellent  combina- 
tion of  materials.  When  they  perspire,  the  cotton  readily 
takes  up  the  perspiration,  leaving  the  skin  dry,  and  the 
layer  of  woolen  next  to  it  gradually  absorbs  and  holds 
the  moisture  without  borrowing  the  body  heat ;  for 


254  PHYSIOLOGY   AND   HEALTH 

woolen  can  absorb  a  large  amount  of  perspiration  with- 
out becoming  wet,  while  cotton  and  linen  cannot. 

Why  Wet  Clothing  Is  Dangerous.  —  The  chief  dis- 
advantage of  wet  clothing  is  that  it  carries  the  body  heat 
away  too  rapidly,  the  water  in  it  being  a  very  good  con- 
ductor. Even  in  summer  this  is  undesirable,  for  a  person 
may  take  cold  on  a  warm  day  from  sitting  still  when 
his  clothing  is  wet  with  perspiration  after  vigorous  exer- 
cise. So  long  as  one  is  active  there  appears  to  be  little 
danger  from  wet  clothing,  even  when  it  is  soaked  from 
rain,  or  from  a  fall  into  the  water ;  for  if  one  is  moving 
about  actively,  enough  more  body  heat  is  generated  to 
compensate  for  the  heat  carried  off  by  the  wet  clothing. 

Cold  Air  Is  a  Tonic.  —  Most  persons  wear  an  unneces- 
sary amount  of  clothing  in  winter,  especially  when  they 
"  bundle  up  "  to  go  out  of  doors.  If  the  thermometer 
goes  below  zero,  special  precautions  must  be  taken ;  in 
ordinary  weather  there  is  no  occasion  for  covering  the 
face  with  veils  and  the  neck  with  furs.  We  are  much 
better  off  if  we  can  accustom  these  parts  of  the  body  to 
the  cold.  Cold  air  produces  the  same  glow  that  comes 
from  a  cold  bath  ;  there  is  tonic  in  it  for  the  air  passages. 
Cold  air  is  much  better  for  the  throat  than  a  layer  of 
fur  wound  tightly  around  it,  for  this  protection  weakens 
the  throat  and  makes  one  more  likely  to  take  cold. 

To  go  to  the  other  extreme  would  be  equally  foolish. 
Shivering  when  one  first  goes  out  into  the  cold  is  good 
exercise  for  the  muscles  and  so  produces  a  little  extra 
heat,  but  the  shivering  ought  to  be  followed  by  an  ex- 
hilarating reaction ;  to  shiver  through  a  five-mile  walk 
means  either  that  one  is  not  walking  fast  enough  (running 


TAKING  CARE  OF  THE  SKIN  255 

a  bit  would  help  warm  the  body),  or  that  the  clothing  is 
not  sufficient  to  enable  the  body  to  retain  its  heat. 

Extra  Protection  for  Exposed  Parts.  —  Our  bodies 
really  live  in  the  temperature  of  the  air  that  is  between 
the  clothing  and  the  skin.  In  cold  weather  the  clothing 
worn  out  of  doors  ought  to  be  sufficient  to  keep  the 
temperature  of  that  inner  layer  of  air  at  about  80°. 
When  extra  clothing  is  required,  the  arms,  legs,  and  feet 
need  more  protection  than  the  rest  of  the  body  because 
they  are  more  exposed  to  the  cold  and  less  able  to  resist 
it,  the  circulation  in  them  being  less  active  than  in  the 
trunk  of  the  body.  Warm  stockings  and  stout  shoes  are 
needed  in  cold  weather,  with  rubbers  whenever  there  is 
danger  of  wetting  the  feet.  We  may  take  cold  from 
sitting  still  with  wet  feet,  because  the  hsat  is  carried  off 
by  the  moisture  faster  than  the  sluggish  circulation  in 
the  feet  can  replace  it.  Rubbers  should  always  be  taken 
off  when  one  goes  indoors ;  otherwise  they  would  prevent 
the  natural  perspiration  from  passing  off  as  it  should. 
(Remember  what  happened  when  you  closed  your  fist 
tight  and  held  it  so  for  a  number  of  minutes.) 

Keeping  Warm  during  Sleep.  —  At  night  people  are 
likely  to  keep  the  air  in  their  sleeping  rooms  too  warm. 
We  rest  much  better  when  we  are  breathing  cold,  invigorat- 
ing air,  but  we  must  be  warmly  covered.  The  body  should 
do  the  least  possible  amount  of  its  regular  work  during 
sleep,  and  when  we  "  sleep  cold,"  it  is  required  to  do  an 
extra  amount  of  work  to  keep  up  the  absolutely  necessary 
degree  of  heat.  The  brain  needs  rest  too ;  if  we  are 
warmly  covered  while  we  are  asleep,  the  part  of  the  brain 
that  is  charged  with  maintaining  the  heat  of  the  body 


256  PHYSIOLOGY   AND   HEALTH 

can  rest,  since  little  body  heat  need  be  made  if  the  bed 
covering  is  sufficient  to  help  retain  what  the  body  has. 
Sometimes  it  is  not  possible  to  get  sufficient  bed  covering 
in  cold  weather,  but  newspapers  are  easily  obtained,  and 
a  few  thicknesses  of  newspaper  placed  firmly  between 
two  thin  blankets  or  quilts  will  make  a  good  covering  for 
holding  in  the  body  heat. 

The  drop  in  heat  production  during  sleep  was  amusingly 
illustrated  in  a  series  of  experiments  upon  a  young  man 
shut  up  in  a  large  copper  box,  to  which  w^ere  attached 
various  appliances  for  measuring  the  amount  of  heat 
made  by  the  body,  the  amount  lost,  etc.  He  was  closely 
watched  all  day ;  and  the  comrades  who  were  reading 
the  different  recording  appliances  knew  how  much  heat 
he  produced  when  he  did  certain  kinds  of  work,  how 
much  when  he  studied,  etc.  When  night  came,  he  went 
to  sleep  at  his  usual  time  and  the  watchers  were  surprised 
to  see  that  the  amount  of  heat  produced  in  his  body 
began  to  decrease  rapidly ;  the  record  went  down,  farther 
and  farther,  until  they  became  thoroughly  alarmed. 
Fearing  that  something  had  gone  wrong  in  the  copper 
box  and  that  their  comrade  was  dying  before  their  eyes, 
in  his  sleep,  they  woke  him,  to  find  that  he  was  perfectly 
well,  and  that  the  alarming  decrease  of  heat  was  only 
natural  when  the  body  was  sleeping  under  the  right 
conditions. 

The  Use  of  Hot  Water.  —  When  we  feel  cold,  the  best 
way  to  get  to  feeling  warm  is  to  take  some  exercise  which 
will  send  the  warm  blood  coursing  through  the  skin; 
that  is  the  way  nature  has  planned  to  give  us  the  sense  of 
being  pleasantly  warm,  by  having  warm  blood  passing 


TAKING  CARE   OF   THE   SKIN  257 

over  the  tiny  sense  organs  in  the  skin.  Another  way  is 
to  apply  heat  to  the  outside  of  the  skin;  a  hot  water 
bag  or  hot  flatiron  are  most  commonly  used,  and  they 
serve  a  good  purpose  when  applied  temporarily.  They 
warm  the  skin  and  also  draw  the  blood  from  the  over- 
supplied  or  congested  interior  of  the  body  to  the  sur- 
face,' thereby  reducing  the  congestion.  Congestion  fre- 
quently causes  severe  pain,  which  such  hot  applications 
often  relieve.  No  outer  heat,  however,  can  take  the 
place  of  body  heat ;  and  if  one  is  accustomed  to 
getting  warm  at  a  hot  stove  or  by  means  of  a  hot 
water  bag,  then  the  skin  after  a  little  fails  to  do  its 
duty,  and  the  person  becomes  unduly  sensitive  to  cold 
and  unable  to  resist  and  to  enjoy  it  as  he  should.  Ex- 
ternal heat  should  therefore  be  applied  to  the  body  only 
for  the  temporary  relief  of  some  unusual  condition. 


QUESTIONS 

1.  What  effect  does  a  hot  bath  have  on  the  temperature  of  the 
body?     On  the  skin?    What  effects  do  cold  baths  have? 

2.  What  happens  to  us  if  we  do  not  bathe  sufficiently? 

3.  Why  do  all  up-to-date  gymnasiums  have  baths  attached?    Are 
there  any  public  baths  in  your  town  ?    Are  there  any  swimming  pools  ? 
Do  you  ever  bathe  in  them? 

4.  If  you  take  a  hot  bath  and  then  go  out  into  the  cold,  how  are 
you  apt  to  feel? 

5.  Should  baths    be    taken    either  immediately  before  or  imme- 
diately  after  meals?     Give  reasons  for  your  answer. 

6.  If  a  person  catches  cold  easily,  would  you  recommend  warmer 
clothing,  or  cold  baths?     Give  reasons  for  your  answer. 

7.  Why  does  your  mother  put  a  cold  bandage  around  your  throat 
when  you  have  a  cold? 


258  PHYSIOLOGY   AND   HEALTH 

8.  Why  do  barbers  apply  hot  and  cold  towels  to  the  face  after 
shaving  ? 

9.  Why  is  it  unwise  to  use  towels  that  have  been  used  by  any  one 
else,  even  if  the  other  person  is  perfectly  well  ? 

10.  Is  it  wise  to  use  the  combs  and  brushes  of  other  people?    Give 
reasons  for  your  answer. 

11.  How  can  you  stimulate  the  growth  of  the  hair?    Do  you  know 
what  to  do  for  hair  that  is  too  dry?     Too  oily? 

12.  Why  is  it  better  to  clean  the  nails  with  a  soft  orange  stick 
than  with  a  steel  file?     Do  you  ever  push  back  the  cuticle  of  your 
nails?    Why  should  you  do  this? 

13.  Besides  improving  the  appearance  of  the  nails,  can  you  think 
of  any  reasons  why  it  is  well  to  stop  biting  them? 

14.  Why  do  we  wear  clothing  ?     If  you  wrapped  a  piece  of  wood  in 
thick  woolen  cloths,  would  the  wood  become  warm?    Give  reasons 
for  your  answer. 

15.  Compare  the  effects  of  wearing  clothing  of  cotton,  linen,  and 
wool,  (a)  in  summer  and  (b)  in  winter.  . 

16.  If  two  boys,  one  barefoot  and  one  wearing  shoes  and  stockings, 
get  their  feet  wet,  which  is  more  apt  to  take  cold  ?    Why  are  your  feet 
apt  to  be  cold  when  they  are  wet  ? 

17.  Why  do  you  shiver  when  you  go  into  a  cold  place?    Is  there 
any  advantage  in  shivering? 

18.  If  a  person  spends  most  of  his  time  indoors,  how  should  he  dress, 
(a)  when  in  the  house  and  (b)  when  he  goes  out  ? 

19.  Is  it  wise  to  go  to  bed  with  cold  feet?    Why  not?     Which  is 
better,  to  warm  them  by  taking  a  hot  water  bag  to  bed,  or  by  slapping 
and  rubbing  them  ? 


CHAPTER   XIII 
SKIN  DEFECTS  AND  DISEASES 

Common  Skin  Defects.  —  Sometimes  the  skin  gets 
much  thickened  at  certain  places.  Boys  are  proud  of  a 
callus  (callosity)  on  their  hands,  caused  by  ball  playing 
or  by  rowing;  the  rubbing  of  the  oar  and  the  striking 
of  the  ball  make  the  epidermis  on  the  hands  grow  more 
rapidly  and  so  it  becomes  thicker.  This  is  nature's 
way  of  protecting  against  injury. 

Corns  on  the  toes  are  formed  in  the  same  way ;  a  tight 
shoe  or  an  ill-fitting  one  that  presses  too  much  on  certain 
parts  of  the  toe  produces  a  decided  thickening  of  the 
skin  at  those  spots.  The  result  is  that  when  the  pressure 
comes  on  the  thickened  parts,  they  do  not  readily  yield ; 
so  the  soft  inner  skin  is  pinched  and  walking  becomes 
more  or  less  painful. 

It  is  much  easier  to  prevent  the  formation  of  corns 
than  it  is  to  get  rid  of  them.  Young  people  who  wear 
shoes  that  are  large  enough  not  to  pinch  the  toes,  and  yet 
snug  enough  not  to  chafe  the  feet,  need  not  fear  corns. 
Children  who  go  barefoot  in  the  summer  do  not  have 
them,  nor  do  they  have  the  misshapen  toes  that  are 
common  in  these  days  when  so  many  people  choose 
their  shoes  because  of  their  attractiveness  rather  than 
with  reference  to  the  shape  and  size  of  their  feet.  If 
you  are  unfortunate  enough  to  have  corns,  they  may 

259 


260  PHYSIOLOGY   AND   HEALTH 

be  kept  from  increasing  in  size  and  from  becoming  pain- 
ful by  wearing  corn  girdles  or  plasters  that  may  be  pur- 
chased at  the  drug  store ;  these  prevent  the  pressure  of 
the  shoe  on  the  corn. 

Some  people  cut  or. shave  their  corns.  This  practice 
is  really  dangerous  because  a  foot  may  be  easily  infected. 
If  one  cuts  so  close  to  the  inner  skin  as  to  draw  blood, 
then  there  is  always  the  risk  of  infection  from  germs  which 
may  cause  sores  on  the  feet.  Blood  poisoning,  with  the 
loss  of  a  toe,  and  sometimes  even  the  loss  of  life,  has  re- 
sulted from  the  cutting  of  corns.  If  a  corn  has  to  be 
cut,  it  is  best  to  go  to  a  chiropodist  or  to  a  doctor,  who 
will  take  every  precaution  to  prevent  trouble.  When 
the  hard  outer  covering  is  removed,  the  wearing  of  a 
corn  plaster  will  make  one  comfortable  for  a  long  time. 

Warts  have,  for  some  reason,  always  been  regarded 
as  mysterious  growths ;  perhaps  it  is  because  they  come 
and  go  without  one's  being  able  to  determine  what 
caused  or  banished  them.  Children  sometimes  believe 
the  stories  about  warts  being  caused  by  handling  toads 
or  by  touching  the  hands  of  those  who  have  warts,  and 
about  their  being  driven  away  by  "  charms."  This  is 
all  nonsense ;  but  there  is  no  doubt  that  warts  will 
usually  go  away  if  they  are  let  alone.  It  is  better  to  let 
them  disappear  than  to  have  them  removed,  unless  they 
grow  so  large  or  are  so  located  that  they  prove  a  great 
inconvenience ;  then  a  physician  can  burn  them  off  with 
acid. 

Blackheads  are  caused  by  the  hardening  of  refuse 
matter  in  the  tiny  openings  of  the  sweat  glands.  To 
prevent  them  the  skin  of  the  face  should  be  kept  active 


SKIN  DEFECTS   AND   DISEASES  261 

and  healthy  by  thorough  cleansing  and  by  continual  wash- 
ing in  cold  water ;  warm  water  relaxes  the  skin  and  is 
likely  to  leave  the  tiny  openings  too  large,  thus  inviting 
the  storing  up  of  the  dust  that  collects  from  the  air,  as 
well  as  the  secretions  thrown  off  by  the  skin. 

Every  one  who  is  in  good  health  should  have  skin  that 
is  smooth  and  soft.  Pimples  show  that  some  organ  of 
the  body  is  not  doing  its  work  properly.  The  trouble  is 
seldom  in  the  skin  itself.  Frequently  the  cause  is  in- 
digestion, and  both  it  and  the  pimples  pass  away  when 
one  eats  properly  and  takes  the  right  amount  of  exercise. 
Often  the  only  remedy  needed  is  to  eat  less  meat  and 
fewer  sweets  and  to  chew  the  food  more  thoroughly. 

Slight  Burns.  —  Most  slight  burns  are  received  by 
touching  some  hot  object,  like  an  oven  door,  an  iron 
handle,  or  a  bucket  of  boiling  water ;  they  may  be  very 
painful,  but  unless  they  are  deep  or  extensive  they  will 
soon  heal  and  be  forgotten.  They  may  be  soothed  by 
keeping  them  covered  from  the  air,  or  simply  by  the 
application  of  cold  water.  One  of  the  best  coverings  for 
an  ordinary  burn  is  a  paste  made  from  vaseline  (or  sweet 
oil)  and  soda  (or  baking  powder).  These  are  usually  at 
hand  and  can  be  quickly  rubbed  together  into  a  paste 
and  applied  to  the  burn  before  it  has  been  long  exposed. 
There  are  various  substitutes  that  may  be  applied  in  an 
emergency,  such  as  linseed  oil,  limewater,  cold  cream, 
or  flour ;  the  object  is  to  cover  the  burn  completely  and 
to  use  nothing  that  will  adhere  to  the  wound  as  cloth  or 
cotton  wadding  does.  As  in  the  case  of  a  wound,  a  burn 
should  always  be  treated  with 'materials  that  are  clean. 

Serious  Burns.  —  The  most  serious  burns  are  caused 


PHYSIOLOGY   AND   HEALTH 

by  coming  in  contact  with  flame,  usually  from  setting 
the  clothing  on  fire.  That  is  the  time  when  life  may  be 
saved  by  keeping  calm  and  by  doing  one  or  two  simple 
things.  Flames  always  rise;  and  the  greatest  danger 
comes,  not  from  the  injury  to  the  skin  but  from  the  in- 
haling of  the  flames,  which  is  sure  to  cause  death.  So 
the  first  thing  to  remember  is  that  instead  of  standing 
or  running  about,  the  person  whose  clothing  is  on  fire 
should  lie  down  on  the  floor.  When  on  the  floor  he  can 
do  more  to  help  himself  than  by  running  about  looking 
for  some  one  to  put  the  fire  out ;  and  while  he  works  he 
can  be  calling  lustily  for  help. 

His  effort  must  be  to  smother  the  flames ;  fire  cannot 
burn  without  air,  and  he  can  keep  the  air  from  the  flames 
by  wrapping  about  himself  the  rug  on  the  floor  or  what- 
ever heavy  covering  he  can  reach  without  running  around 
after  it  —  a  blanket  from  the  bed,  a  coat,  a  heavy  drapery 
torn  from  the  window,  or  an  end  of  the  carpet  pulled  up. 
If  there  is  no  woolen  stuff  or  heavy  covering  within 
reach,  the  best  thing  to  do  is  to  roll  over  and  over  on  the 
floor,  as  rapidly  as  possible;  this  alone  will  usually 
put  out  the  fire. 

The  part  of  the  bystander  is  to  do  what  the  burning 
man  may  forget  to  do.  Knock  him  down  if  he  starts  to 
run.  Remember  that  it  is  better  to  smother  the  flames 
in  some  woolen  covering  than  to  attempt  to  beat  them 
out  with  the  hands.  After  the  fire  is  out,  the  clothing 
must  be  carefully  removed.  In  case  of  severe  burns  the 
clothing  will  be  apt  to  stick  to  the  burned  part ;  it  should 
not  be  torn  away,  but  should  be  cut  off.  Cover  the 
burned  places  until  a  physician  can  decide  what  had 


SKIN  DEFECTS  AND   DISEASES  263 

best  be  done.  In  the  meantime,  if  the  physician  cannot 
come  immediately,  the  burned  surfaces  should  be  covered 
with  something,  like  the  paste  recommended  above, 
that  will  keep  the  air  out  and  that  may  be  readily  re- 
moved without  injury  to  the  burned  skin. 

Frostbites. --The  ears,  the  nose,  the  fingers,  and  the 
toes  are  particularly  susceptible  to  frostbite,  which  may 
be  a  mild  form  of  freezing  or  the  actual  turning  of  the 
blood  and  muscles  into  ice.  These  extremities  are  not 
only  more  exposed  than  other  parts  of  the  body,  but  the 
circulation  of  the  blood  in  them  is  much  less  rapid.  We 
might  expect  that  they  would  be  the  first  to  freeze, 
because  we  know  that  still  water  freezes  more  quickly 
than  running  water.  In  ordinary  frostbites  no  permanent 
injury  results  if  the  frozen  parts  are  thawed  out  slowly, 
but  serious  trouble  may  follow  rapid  thawing,  even  the 
necessity  of  amputating  toes  or  fingers.  Rubbing  the 
parts  in  snow  or  in  cold  water  is  recommended.  The 
rubbing  will  thaw  the  part,  and  the  snow  will  prevent 
the  thawing  from  taking  place  too  rapidly.  Evidently 
it  would  be  unwise  to  place  the  patient  before  a  fire  or 
in  a  warm  room,  but-  he  should  be  well  bundled  up  in 
blankets  while  the  frozen  part  is  being  gradually  thawed. 
After  thawing  it  should  be  covered  to  keep  out  the  air, 
and  in  general  treated  as  a  burn. 

Chilblains.  —  Frostbite  is  wrongly  credited  with  being 
the  cause  of  a  painful  ailment  of  the  feet  known  as  "  chil- 
blains." Getting  the  feet  very  cold  and  wet  and  then 
warming  them  too  quickly  is  the  most  frequent  cause  of 
chilblains.  One  is  laying  the  foundation  for  chilblains 
when  he  warms  his  feet  over  a  register  or  in  a  stove  oven, 


264  PHYSIOLOGY   AND   HEALTH 

or  heats  them  every  night  on  a  hot  water  bag.  The  best 
protection  against  chilblains  is  to  wear  warm  stockings 
and  thick  shoes  in  cold  weather,  and  to  give  the  feet 
plenty  of  exercise.  The  symptoms  are  a  burning  and  an 
intense  itching  of  the  sides  of  the  feet,  the  toes,  and  the 
heels. 

Skin  Infections.  —  It  used  to  be  said  that  boils,  ab- 
scesses, skin  eruptions,  erysipelas,  and  blood  poisoning 
were  due  to  "  the  condition  of  the  blood  " ;  but  since 
men  have  learned  more  about  the  action  of  microbes, 
most  of  these  troubles  have  been  traced  to  the  entrance 
into  the  body  of  disease  germs  through  the  skin.  The 
germs  which  cause  most  skin  troubles  are  very  much 
alike.  They  are  found  on  our  clothes,  on  our  hands  and 
faces,  and  in  our  mouths,  but  they  do  no  harm  until  they 
get  through  the  guard  formed  by  the  outer  skin  and 
enter  into  the  blood  or  lymph.  A  bruise  or  even  a  scratch 
in  the  skin  gives  them  entrance ;  what  happens  next 
depends  upon  the  condition  of  the  blood,  that  is,  upon 
the  ability  of  the  white  corpuscles  to  conquer  the  disease 
microbes. 

If  the  microbes  win  the  contest,  a  characteristic  form 
of  inflammation  usually  results  from  their  growth.  A 
good  healthy  body  often  has  power  enough  to  resist 
the  ravages  of  these  particular  germs  and  to  prevent 
their  growing,  even  after  they  get  into  the  body  through 
the  skin.  If  a  person  finds  that  every  scratch  becomes 
inflamed,  if  he  keeps  having  boils,  he  may  know  that  his 
body  is  warning  him,  as  plainly  as  possible,  that  it  has 
lost  much  of  its  power  of  resisting  the  attack  of  the  germs 
that  may  get  in  through  the  skin.  What  he  needs  is, 


SKIN  DEFECTS  AND   DISEASES  265 

not  to  get  a  skin  lotion,  but  to  follow  the  general  laws  of 
good  health. 

Bruises,  cuts,  and  scratches  are  an  invitation  to  the 
microbes,  since  they  all  make  breaks  in  the  protecting  outer 
skin.  They  should  therefore  be  promptly  and  carefully 
cleansed.  The  invading  germs  are  easily  disposed  of  in  the 
beginning,  but  hard  to  fight  when  they  get  a  start.  All 
wounds  should  be  treated  with  an  antiseptic  solution, 
either  iodine  or  carbolic  acid  (one  part  to  twenty  of 
water),  which  will  destroy  the  germs.  It  is  always  ad- 
visable to  keep  on  hand  a  bottle  of  tincture  of  iodine  or 
some  antiseptic  ointment,  and  to  get  into  the  habit  of 
washing  all  cuts  and  scratches  with  it.  Then  when  they 
are  made  clean,  forget  about  them.  Many  troublesome 
sores  may  be  prevented  by  this  simple  precaution.  After 
the  wound  has  been  cleansed,  it  should  be  covered  with 
a  bandage  of  clean  cloth  to  bar  out  the  microbes  in  the 
air. 

Deep  wounds  frequently  do  not  bleed  much,  and  so 
they  may  appear  less  serious  than  surface  wounds  that 
bleed  profusely;  but  the  slight  bleeding  is  really  a  dis- 
advantage, because  germs  are  likely  to  be  washed  away 
from  an  open,  bleeding  wound,  while  those  carried 
deeply  into  the  flesh  by  a  nail,  or  needle,  or  splinter 
may  remain  there  and  make  serious  trouble.  The  object 
that  produces  the  wound  should  therefore  be  removed. 
This  is  sometimes  a  very  difficult  thing  to  do  when  a 
piece  of  glass  or  a  long  splinter  is  imbedded  in  the  flesh, 
especially  under  the  finger  nail ;  but  to  leave  it  would 
mean  danger.  After  it  has  been  removed,  the  wound 
should  be  made  to  bleed  freely,  thus  washing  away  as 


266  PHYSIOLOGY  AND   HEALTH 

many  as  possible  of  the  dangerous  microbes.  Then  the 
wound  should  be  treated  with  iodine,  and  if  possible  some 
of  the  iodine  should  be  injected  into  the  wound,  a  hard 
rubber  syringe  being  used  for  this  purpose.  A  deep 
wound  should  have  the  care  of  a  physician,  and  if  one 
cannot  be  secured  immediately,  iodine  should  be  used 
promptly. 

Lockjaw.  —  A  wound  made  by  a  rusty  nail,  or  a  dirty 
sliver  of  wood  that  has  been  lying  on  the  ground,  is 
likely  to  be  dangerous.  Rust  does  not  produce  lockjaw, 
but  if  a  nail  has  been  lying  around  long  enough  to  rust, 
it  has  also  had  time  to  become  the  lodging  place  for 
many  microbes.  In  some  parts  of  the  world  the  soil 
contains  a  deadly  microbe  which  produces  lockjaw.  It 
is  most  common  in  soil  that  has  been  under  high  cultiva- 
tion. Yet  there  are  few  places  where  one  can  be  free  from 
danger  from  these  microbes ;  any  dirty  object  may  have 
some  of  them  clinging  to  it.  Toy  pistols,  whose  sale 
many  cities  now  forbid,  especially  on  the  Fourth  of 
July,  are  particularly  dangerous  because  a  boy's  hands 
are  apt  to  be  dirty  from  firing  this  pistol.  By  the  explosion 
of  the  pistol  the  dirt  may  be  carried  into  the  skin,  and 
perhaps  with  it  the  lockjaw  (tetanus)  microbe. 

Lockjaw  is  practically  always  fatal,  so  that  the  only 
way  to  fight  it  is  to  prevent  it.  The  best  prevention  is 
to  make  every  deep  wound  absolutely  clean  by  a  daily 
antiseptic  cleansing.  A  deep  wound  should  not  be 
allowed  to  heal  at  the  surface  because  the  lockjaw  mi- 
crobe, which  cannot  grow  when  exposed  to  the  air,  may 
thrive  and  become  dangerous  if  tucked  away  undisturbed 
in  a  deep  wound.  A  deep  wound  should  be  covered 


SKIN  DEFECTS  AND   DISEASES  267 

constantly  with  a  clean  cloth,  but  should  be  kept  open, 
for  a  time,  at  the  surface.  Since  microbes  may  render 
even  slight  wounds  dangerous,  it  is  foolish  to  run  about, 
carelessly,  with  sharp  objects  in  the  hands  or  in  the 
mouth.  Many  young  people  have  lost  limbs  or  eyes 
because  of  simple  carelessness  with  knives,  scissors,  and 
buttonhooks. 

Cuts  and  bruises  on  the  feet  should  be  even  more  carefully 
treated  than  wounds  elsewhere.  They  should  be  cleaned 
at  once,  washed  with  an  antiseptic  solution,  —  iodine  is 
the  best,  —  and  then  they  should  be  firmly  covered 
with  clean  cloth  before  the  stocking  is  replaced.  This 
will  prevent  many  a  sore  toe  arid,  perhaps,  something 
more  serious,  like  blood  poisoning.  The  necessity  for 
these  precautions  is  evident  when  we  realize  that  any 
sore  on  the  foot,  even  a  small  break  around  a  toe  nail, 
is  aggravated  by  being  shut  up  in  the  shoe,  and  by  the 
moist  stocking  continually  rubbing  against  it.  These 
are  ideal  conditions  for  the  microbes,  and  the  stocking 
is  almost  sure  to  harbor  many  disease  germs  which 
only  need  warmth  and  moisture  in  order  to  grow  rapidly. 

Fishhook  wounds  are  usually  quite  shallow ;  if  the  barb 
makes  it  difficult  to  remove  the  hook,  push  the  point 
through  the  skin ;  then  the  barb  can  be  cut  off  with  a 
wire  cutter,  and  the  hook,  minus  the  point,  is  easily 
removed. 

Bites  of  animals  used  to  be  considered  dangerous, 
because  of  some  mysterious  poison  that  was  said  to  be 
made  in  the  mouths  of  angry  animals.  In  fact  they  are 
more  dangerous  than  ordinary  wounds,  but  only  because 
dangerous  germs  are  usually  lodged  in  an  animal's  mouth. 


268  PHYSIOLOGY   AND   HEALTH 

For  the  same  reason  the  bite  of  another  person  is  even 
more  dangerous  than  the  bite  of  an  animal.  An  anti- 
septic wash  should  always  be  used  in  such  wounds. 

Rabies.  —  The  bite  of  a  dog  is  especially  feared  be- 
cause it  sometimes  produces  a  much-dreaded  disease 
called  rabies  or  hydrophobia.  This  disease  is  one  of  the 
most  painful  and  practically  always  fatal.  But  dog 
bites  cannot  cause  hydrophobia  unless  the  dog  is  at  the 
time  suffering  from  the  disease.  A  rabid  dog  does  not 
yelp  or  bark,  and  does  not  froth  at  the  mouth,  though  a 
brownish  mucus  may  hang  from  his  mouth.  He  usually 
jogs  along  slowly  through  the  streets,  paying  little  atten- 
tion to  anything,  but  is  likely  to  snap  or  bite  if  anything 
comes  in  his  way.  He  does  not  dread  water  as  is  com- 
monly believed.  One-  such  dog  sometimes  travels  for 
many  miles,  biting  many  other  dogs  on  his  travels  and 
thus  giving  them  the  disease. 

Often  a  healthy  dog  is  tormented  or  frightened  until  it 
tries  to  bite  every  one  who  goes  near  it ;  some  boy  gets 
too  close  and  is  bitten.  Then,  fearing  the  dog  is  "  mad/7 
somebody  will  probably  propose  that  it  be  killed  at 
once.  This  is  a  very  short-sighted  thing  to  do  ;  instead, 
the  dog  should  be  shut  up  safely  where  it  cannot  bite 
people  or  other  dogs  and  given  food  and  a  chance  to 
recover.  If  really  rabid,  it  will  surely  die  within  a  day 
or  two.  //  it  does  not  die,  it  was  not  a  mad  dog. 

Should  it  die,  the  head  should  be  sent  to  some  proper 
laboratory,  where  an  examination  will  quickly  show 
whether  the  dog  really  had  rabies.  Remember  that 
the  disease  is  uncommon.  Dogs  get  it  by  being  bitten  by 
other  dogs  who  have  the  disease ;  they  are  no  more 


SKIN  DEFECTS   AND    DISEASES  269 

likely  to  have  it  in  hot  weather  (sometimes  called  "  dog 
days  ")  than  in  winter.  Human  beings  get  it  wholly 
from  animals,  chiefly  from  dogs,  though  occasionally 
from  the  bite  of  cats  or  wolves,  or  even  of  skunks.  Many 
absurd  stories  are  told  about  this  disease.  Sometimes 
one  hears  that  a  person  bitten  by  a  well  dog  will  have  the 
disease  if  that  dog  should  at  any  time  afterwards  develop 
it.  This  is  sheer  nonsense,  for  the  germs  of  the  disease 
must  actually  be  in  the  animal's  mouth  when  he  bites, 
in  order  to  produce  the  disease.  How  many  people 
do  you  know  who  have  ever  seen  a  mad  dog? 

Any  one  who  is  bitten  by  a  dog  that  is  really  rabid  or 
that  is  strongly  suspected  of  being  rabid  should  be  taken 
at  once  to  a  Pasteur  Institute,  where  he  can  be  given  a 
treatment  that  will  usually  prevent  the  development  of 
the  disease.1  This  treatment  can  be  given  by  an  ordinary 
physician,  and  it  must  be  begun  quickly.  If  delayed 
more  than  two  or  three  days  after  the  person  is  bitten, 
there  is  much  less  chance  of  preventing  the  disease ;  if  it 
can  be  begun  at  once,  it, is  almost  sure  to  be  effective. 

Rabies  would  soon  be  stamped  out  entirely  if  all  the 
dogs  in  the  world  could  be  muzzled  for  a  short  time, 
since  it  is  only  distributed  by  biting.  England  succeeded 
in  getting  rid  of  rabies  by  simply  muzzling  all  its  dogs. 

Diseases  with  Skin  Eruption. -- The  most  common 
diseases  that  are  accompanied  by  a  skin  eruption  arc 
scarlet  fever,  measles,  chicken  pox,  and  smallpox.  Scarlet 
fever  is  a  severe  and  sometimes  fatal  illness;  the  most 
serious  feature  of  it  is  the  effect  produced  by  its  poison 

1  Many  states  furnish  the  treatment  free  to  anyone  who  cannot  pay 
for  it. 


270  PHYSIOLOGY  AND  HEALTH 

on  the  kidneys  and  other  internal  organs.  Measles  also 
sometimes  ends  fatally.  The  skin  eruption  gives  much 
discomfort,  and  the  eyes  are  often  seriously  affected. 
Chickenpox  is  rarely  serious.  The  germs  that  cause 
these  diseases  are  not  yet  known,  but  the  infection 
probably  passes  from  the  nose  or  the  skin  of  the  patient. 

All  of  these  diseases  are  very  contagious ;  the  spread- 
ing of  them  can  be  avoided  only  by  keeping  those  affected 
isolated  until  they  can  no  longer  convey  the  infection 
to  others ;  that  is,  from  two  to  six  weeks,  varying  with 
the-  different  diseases.  Most  towns  and  cities  have 
regulations  covering  these  and  other  contagious  diseases, 
which  are  designed  to  prevent  them  from  being  carried 
from  one  person  to  another  and  becoming  epidemic. 
All  good  citizens  ought  to  be  willing  to  follow  such  regu- 
lations. The  nation  has  a  right  to  expect  that  every 
citizen  shall  try  to  be  a  well  citizen. 

Smallpox.  —  In  former  times  smallpox  was  a  frightful 
scourge.  It  not  only  caused  an  immense  number  of 
deaths,  but  its  victims  who  recovered  were  often  made 
unsightly  by  the  "  pitting  "  of  their  faces.  To-day  it  is 
placed  in  the  class  of  preventable  diseases;  epidemics 
of  it  are  rare  because  men  know  how  to  fight  it.  There 
are  two  factors  in  fighting  it :  (1)  isolation  and  (2)  vac- 
cination. 

People  who  have  had  smallpox  are  usually  immune 
to  it,  i.e.  they  will  not  have  it  a  second  time ;  certain 
changes  have  taken  place  in  the  body  which  are  a  defense 
against  the  disease.  The  object  of  vaccination  is  to 
produce  a  similar  condition  and  to  make  one  immune  to 
smallpox  but  without  having  the  disease.  This  is  done  by 


SKIN  DEFECTS  AND   DISEASES  271 

scraping  off  a  bit  of  the  outer  skin  of  the  arm  and  touch- 
ing the  live  skin  with  a  "  point  "  that  contains  the  virus 
of  cowpox,  a  very  mild  form  of  smallpox.  If  the  virus 
"  takes,"  the  person  vaccinated  usually  has  a  slightly 
sore  arm,  generally  not  sore  enough  to  keep  him  from 
work,  and  his  blood  is  temporarily  made  immune,  not 
only  to  cowpox,  but  also  to  smallpox.  This  immunity 
lasts  from  three  to  ten  years.  In  countries  where  vac- 
cination is  enforced  by  law  the  number  of  cases  of  small- 
pox is  small.  Physicians  who  are  treating  smallpox 
patients  are  themselves  vaccinated  every  few  years,  and 
it  is  seldom  that  one  of  them  takes  the  disease.  Small- 
pox has  practically  disappeared  from  countries  where 
every  one  is  obliged  to  take  this  precaution. 

QUESTIONS 

1.  Have  you  ever  had  callous  spots  on  your  hands  or  feet?    If  so, 
what  caused  them  ?     Did  they  hurt  ?     How  did  you  get  rid  of  them  ? 

2.  If  a  corn  is  composed  of  dead  skin,  what  makes  it  hurt?    Can 
you  think  of  any  reason  why  a  person  who  suffers  much  from  corns 
is  likely  to  suffer  also  in  his  general  health  ? 

3.  Why  do  doctors  tell  you  to  treat  a  bad  complexion  "from  in- 
side" instead  of  depending  on  salves  and  ointments? 

4.  What  is  the  cause  of  most  skin  diseases?     In  clearing  the  skin 
of  imperfections,  what  are  the  most  important  things  to  do?     Can 
one  person  give  such  diseases  to  another? 

5.  Why  does  not  the  doctor  in  the  laboratory,  who  is  continually 
handling  disease  germs,  always  contract  the  disease  ? 

6.  When  disease  germs  get  into  the  body,  what  part  of  the  body 
has  the  duty  of  getting  rid  of  them  ?     Do  the  white  corpuscles  always 
win  in  the  fight?     If  not,  what  happens? 

7.  Can  you  think  of  any  reason  why  it  is  a  law  of  nature  that  cuts 
and  bruises  should  hurt? 


272  PHYSIOLOGY  AND   HEALTH 

8.  What  should  always  be  done  when  the  skin  is  cut  or  scratched 
or  burned?     Why  should  one  take  special   care  of  wounds  on  the 
feet? 

9.  What  is  meant  by  an  antiseptic?     What  antiseptic  have  you 
in  your  home?    Do  you  know  where  it  is  kept  and  how  to  use  it? 
What  is  meant  by  a  sterile  bandage  ?    How  is  a  bandage  sterilized  ? 

10.  Why  does  a  doctor  wash  his  hands  so  carefully  before  treating 
wounds  ?     Why  is  a  dirty  wound  more  dangerous  than  a  clean  one  ? 

11.  What  is  the  most  important  thing  to  remember  in  case  of  fire? 
If  the  clothing  of  a  pupil  in  your  class  should  catch  fire,  what  would 
you  do?    What  would  you  use  to  put  out  the  fire?    If  the  fire  hap- 
pened in  your  own  living  room,  what  could  you  use  ? 

12.  Why  is  it  that  bad  burns  are  so  dangerous?    What  must  you 
remember  in  treating  burns?     If  some  one  in  your  home  should  be 
burned,  do  you  know  where  to  find  the  things  needed  for  treatment  ? 

13.  What  parts  of  the  body  are  most  apt  to  be  frostbitten?    Why? 
Why  should  not  frostbitten  people  be  brought  into  a  warm  room? 
How  should  they  be  cared  for? 

14.  Have  you  ever  had  chilblains?     Do  you  know  what  causes 
them  ?    What  can  one  do  to  avoid  them  ? 

15.  Why  is  lockjaw  so  dangerous?     How  can  the  germs  of  lockjaw 
be  carried  into  the  body? 

16.  Is  there  any  law  in  your  town  or  state  forbidding  the  sale  of 
toy  pistols?    Why  is  a  toy  pistol  dangerous? 

17.  If  you  were  bitten  by  a  strange  dog,  what  ought  you  to  do? 
How  can  a  doctor  find  out  if  a  dog  really  was  mad  ?    If  you  see  a  dog 
that  you  think  is  mad,  what  is  the  best  thing  to  do  ? 

18.  Why  is  it  that  children  who  have  measles,  scarlet  fever,  etc., 
are  not  allowed  to  go  to  school  even  if  they  are  not  very  sick  ? 

19.  Are  there  any  laws  in  your  town  forbidding  children  from  homes 
in  which  there  are  contagious  diseases,  from  going  to  school? 

20.  Why  do  most  cities  require  that  school  children  shall  be  vac- 
cinated ?    Is  there  as  much  smallpox  now  as  there  used  to  be  ? 


SECTION  III 
HOW  THE  BODY  IS  GOVERNED 

CHAPTER  I 
THE   GOVERNING   MECHANISM 

The  Need  of  Direction.  —  The  different  parts  of  the 
body  could  never  do  their  work  properly  if  they  were 
not  directed  by  some  central  authority,  which  relates 
one  to  the  other  and  decides  which  of  them  may,  at  any 
time,  have  extra  blood,  when  each  shall  rest,  and  when 
each  shall  work.  Just  imagine  what  chaos  would  result 
if  the  organs  were  allowed  to  direct  their  own  work.  The 
stomach  might  secrete  all  its  juices  and  do  all  its  churn- 
ing at  night,  when  there  was  no  food  to  digest ;  the  muscles 
might  start  to  get  their  work  for  the  day  done  early  in  the 
morning  and  later  be  too  tired  to  carry  us  about ;  the 
heart  might  try  to  work  on  the  stomach's  schedule,  two 
or  three  hours  of  continuous  work  followed  by  an  hour  or 
two  of  rest :  there  is  no  limit  to  the  accidents  that  might 
occur  if  every  part  of  the  body  were  not  held  to  strict 
account  by  some  central  authority  which  told  it  just  when 
to  do  its  work  and  how. 

The  Neurons 

The  Individuals  That  Compose  the  Nervous  System.  — 
The  government  of  the  body  is  controlled  by  the  nervous 

273 


274 


PHYSIOLOGY   AND   HEALTH 


system,  which  is  like  a  highly  organized  army.  The 
individual  soldiers  composing  this  army  are  called 
neurons.  They  cannot  be  seen  without  the  microscope. 
Figure  79  shows  how  they  look  under  the  microscope. 
Near  the  center  there  is  an  irregular-shaped  body,  con- 
taining within  it  a 
smaller  body,  called  a 
nucleus.  From  the 
neuron  body  a  few 
branches  are  given 
off,  each  of  which 
soon  divides  into  nu- 
merous fine  branches, 
called  dendrites 
(really  much  finer 
than  those  shown  in 
the  figure).  One  of 
the  branches,  instead 
of  dividing,  extends 
away  from  the  neuron 
body  undivided,  and 
finally,  as  a  nerve  fiber,  joins  other  nerve  fibers  to  form 
a  nerve  trunk.  The  nerve  fiber  may  be  very  long  or 
very  short.  The  longest  nerve  fibers  are  those  extending 
to  the  toes ;  these  have  their  beginnings  in  neuron  bodies 
somewhere  up  in  the  spinal  cord.  The  one  long  branch 
of  a  neuron  is  called  its  axon. 

The  neuron  army  is  a  big  one  indeed,  for  there  are 
some  9,000,000,000  neurons  in  the  brain,  each  with  its 
dendrites  and  its  axon.  That  explains  why  it  takes  years 
to  get  this  army  properly  trained,  and  why  children  have 


FIG.  79.  —  Two  NEURONS. 


THE   GOVERNING  MECHANISM  275 

to  spend  so  much  time  in  school ;  for  studying  is  one  of  the 
chief  means  of  training  these  brain  soldiers  to  do  their 
work. 

When  we  speak  of  the  work  done  by  the  nervous 
system  we  are  really  speaking  of  the  work  of  neurons. 
Tiny  as  they  are,  each  has  its  own  work  to  do,  and 
each  may  call  upon  the  others  for  help  or  direction  if 
necessary. 

The  Duties  of  the  Neurons.  —  These  tiny  neurons 
really  control  all  the  actions  of  the  body.  One  of  their 
principal  duties  is  to  control  the  muscles  by  giving  them 
orders.  Each  muscle  fiber  has  a  nerve  fiber  (an  axon) 
attached  to  it,  the  other  end  of  which  is  in  a  neuron  body 
somewhere  in  the  spinal  cord  or  brain.  The  neuron  in  the 
brain  gives  an  order  which  travels  down  the  nerve  fiber, 
at  the  rate  of  about  100  feet  per  second,  till  it  reaches  the 
muscle  fiber ;  the  muscle  obeys  by  contracting.  But  it 
is  not  muscles  alone  that  are  controlled  by  neurons.  The 
secretion  of  the  glands,  the  circulation  of  the  blood,  and 
even  our  sensations  and  our  thinking  are  regulated  by 
neurons. 

The  Organization  of  the  Neurons.  • —  Individual  soldiers 
do  not  make  an  army  until  they  are  properly  organized ; 
this  is  equally  true  of  the  neurons.  The  organization 
of  an  army  is  so  much  like  that  of  the  nervous  system 
that  it  will  help  us  to  understand  this  system  if  we  con- 
sider how  things  are  arranged  in  an  army.  Starting 
at  the  top,  we  shall  find  that  an  army  has  a  commanding 
general  who  makes  the  plans  for  the  whole  army.  This 
general  does  not  have  time  to  give  commands  to  the 
individual  soldiers;  he  has  many  subordinate  officers 


276 


PHYSIOLOGY   AND    HEALTH 


who  attend  in  different  ways  to  the  carrying  out  of  his 
plans.  There  are  majors,  captains,  and  lieutenants, 

each  in  charge  of  bodies 
of  men,  and  below  these 
are  the  sergeants  and 
corporals,  each  with  his 
subordinate  share  in 
carrying  out  the  plans 
of  the  commanding  gen- 
eral. Finally  there  are 
the  soldiers  themselves, 
each  with  his  particular 
duty  to  perform.  In  a 
well-drilled  army  each 
soldier  and  each  officer 
has  learned  his  duty  and 
his  relation  to  all  the 
others,  so  that  the  orders 
of  the  general  are  in- 
stantly and  efficiently 
carried  out.  Such  a 
well-organized  army  can 
win  victories. 

Now  while  this  illus- 
tration cannot  be  carried 

FIG.  80.  —  THE  NERVOUS  SYSTEM.  QU^    jn    every   respect    as 

Showing  the  br^the^mal  cord,  and  tiie     applied     to     Qur     bodiegj 

it  does  give  us  a  good 

idea  of  how  the  duties  of  the  nervous  system  are  divided. 
We  might  make  the  comparison  as  follows.  (It  is  for 
reference  only,  not  to  be  learned.) 


THE   GOVERNING  MECHANISM  277 

Commanding  general  Cerebrum 


Major  officers  Cerebellum    }     ram 

Quartermaster  (in  charge  of    ,  ,   ,  „ 

,.    ,  Medulla 

supplies) 

Petty  officers  Spinal  cord 

Common  soldiers  Neurons 

Sentries  and  scouts  Sensory  nerves 

Messengers  to  carry  orders  Motor  nerves 

The  nervous  system  is  really  a  much  more  complicated 
organization  than  this;  moreover,  we  must  remember 
that  the  cerebrum  not  only  contains  the  commander  in 
chief  but  also  countless  numbers  of  the  individual  neuron 
soldiers.  Yet  in  spite  of  these  differences  the  comparison 
very  well  suggests  how  the  different  parts  of  the  nervous 
system  are  related.  Let  us  now  see  what  these  parts  are. 

The  Cerebro-spinal  System 
The  Cerebro-spinal  System  consists  of  three  parts : 

Brain 

Spinal  cord 
Nerves 

The  Brain.  —  The  brain  is  one  of  the  most  complicated 
structures  in  existence.  It  is  also  one  of  the  most  deli- 
cate organs  in  the  body,  and  for  protection  it  is  in- 
closed in  a  bony  box  called  the  skull.  It  can  never  be 
observed  directly  except  in  cases  where  through  some 
accident  part  of  the  bony  covering  is  removed.  It  weighs 
about  three  pounds  in  a  grown  person,  being  approxi- 


278  PHYSIOLOGY   AND   HEALTH 

mately  ^  of  the  entire  weight.  Other  animals  have 
brains  of  greater  or  less  size,  but  even  the  most  intel- 
ligent of  them  have  brains  that  are  either  much  smaller 
than  man's,  or  smaller  in  proportion  to  the  weight  of 
their  bodies ;  the  brain  of  the  elephant  is  -^  of  his 
weight,  that  of  the  chimpanzee  -fa  of  his. 

The  brain  is  divided  into  three  parts.     These  three  parts 
are  no  more  separated  from  one  another  than  are  the  arm 


FIG.  81.  —  THE  HUMAN  BRAIN. 

and  the  hand,  but  as  their  structure  is  different  and  their 
work  different  it  is  easier  to  consider  them  separately. 
These  parts  are  called  the  cerebrum,  the  cerebellum,  the 
medulla  oblongata. 

The  Cerebrum.  —  The  largest  part  of  the  brain  is  the 
cerebrum,  it  being  seven-eighths  of  the  entire  brain.     Its 


THE   GOVERNING  MECHANISM 


279 


surface  is  deeply  folded.  The  folds  are  called  convolu- 
tions, and  the  deeper  the  folds  the  greater  the  brain  power 
of  the  individual.  Some  animals,  like  frogs,  snakes,  and 
birds,  have  practically  no  brain  convolutions ;  but  they 
are  found  in  the  higher  animals,  like  monkeys,  though  they 
are  not  so  numerous  or  so  deep  as  those  in  a  man's  brain. 
There  is  a  very  deep  furrow  in  the  cerebrum  which  divides 
it  into  two  (connected)  halves,  called  the  right  hemisphere 
and  the  left  hemisphere.  Here  we  discover  one  of  the 
brain's  many  surprises,  for  the  right  hemisphere  proves 
to  have  charge  of  the  left  side  of  the  body,  and  the  left 
hemisphere  of  the  right  side  of  the  body. 

The  cerebrum  looks  gray,  for  the  outside  of  it,  to  a  depth 
of  about  three-sixteenths  of  an  inch,  consists  of  countless 
neurons  massed 
together,  making 
what  is  called 
gray  matter  (Fig- 
ure 82) ;  below 
that  is  white  mat- 
ter, which  consists 
of  a  mass  of  axons. 
We  already  know 
that  there  is  a  de- 
cided difference  in 
the  kind  of  work 
done  by  neurons 

and  axons  and  in  their  methods  of  working.  The  mass  of 
neurons  which  makes  the  outer  surface  of  the  cerebrum 
is,  for  convenience,  called  the  cortex.  It  is  the  cortex  that 
thinks,  receives  sensations,  and  gives  orders  that  cause 


FIG.  82.  —  A  BIT  OF  THE  CEREBRUM. 

Showing   numerous  neurons  and  their  dendrites 

highly  magnified. 


280  PHYSIOLOGY   AND   HEALTH 

movements  in  different  parts  of  the  body ;  all  the  conscious 
movements  in  the  body  are  regulated  by  the  cortex. 

The  Cerebellum.  —  Below  the  cerebrum  and  partly 
covered  by  it,  is  another  part  of  the  brain,  called  the 
cerebellum ;  it  is  not  larger  than  a  lemon,  and  has  many 
furrows  that  go  across  it  from  side  to  side.  One  of 
its  chief  duties  seems  to  be  to  relieve  the  cerebrum  of  the 
necessity  of  giving  constant  attention  to  the  condition  of 
the  voluntary  muscles.  It  takes  many  muscles  working 
together  to  produce  such  a  motion  as  throwing  a  stone, 
walking,  or  skating.  The  cerebellum  makes  all  the  muscles 
involved  act  in  harmony,  so  as  to  produce  the  desired 
motion.  We  call  this  marvelous  power  coordination. 
The  cerebellum  contains  some  of  the  subordinate  officers 
that  produce  this  coordination.  When  the  cerebrum  wants 
the  body  to  walk,  it  sends  a  message  to  the  proper  officer 
and  then  pays  no  further  attention. 

From  observations  on  frogs  it  is  thought  that  most 
movements  could  be  made  by  the  cerebellum  without  the 
help  of  the  cerebrum.  The  cerebellum  of  the  frog  could 
direct  the  motions  involved  in  jumping  from  the  shore 
into  the  water ;  but  if  the  frog  had  no  cerebrum,  it  would 
not  try  to  jump  unless  some  outside  stimulus,  like  the 
pinching  of  a  hind  leg,  started  the  motion.  Otherwise, 
lacking  the  cerebrum  which  usually  gives  the  cerebellum 
its  commands,  the  frog  would  just  sit  on  the  bank  and  die, 
able  to  move  but  lacking  orders  to  move. 

The  Medulla  Oblongata.  -  -  The  cerebrum  and  cere- 
bellum are  connected  with  the  spinal  cord  by  the  medulla 
oblongata.  This  is  only  three-fifths  of  an  inch  thick, 
and  about  an  inch  long,  yet  this  small  part  of  the  brain  is 


THE  GOVERNING  MECHANISM 


281 


absolutely  indispensable  to  life,  not  simply  because  it 
connects  the  brain  and  the  cord,  but  because  it  has  im- 
portant work  of  its  own  to  do.  It  controls  the  heart-beat, 
the  contractions  of  the  blood  vessels,  and  breathing ;  with- 
out these  functions  life  could  not  go  on.  Life  of  a  limited 
sort  can  go  on  without  the  cerebrum  and  the  cerebellum, 
provided  that  the  medulla  is  still  connected  with  the 
breathing  muscles.  This  is  proved  by  cases  where  in- 
juries to  the  spinal  cord  have  so  broken  the  connections 
that  the  cerebrum  and  cerebellum  have  no  longer  any 
connection  with  the  limbs  or  the  trunk,  although  the 
breathing  center  was  still  connected  with  the  breathing 
muscles.  The  injured  men  had  no  sensations  in  limbs 
or  trunk,  but  lived  for  years,  and  were  able  to  think 
and  of  course  to  breathe,  but  not  to  move.  The  medulla 
has  other  duties  also  besides  those  mentioned. 

The  Spinal  Cord.  —  We  have  already  seen  that  the 
spinal  cord  is  so  pro- 
tected  by  the  verte- 
brae  that  it  receives 
surprisingly  little  in- 
jury from  falls,  blows, 
or  other  accidents. 
The  soft  membranes 
that  cover  it  also 
serve  as  another 

means    Of    protection.     About  four  times  natural   size.     A.r.,  anterior 

The     cord     extends       root ;  G-m- gray  matter :  p-r-  p°sterior  r°Gt ; 

*Sp.0.,  spinal  ganglion ;   W.m,,  white  matter. 

from     the      medulla 

nearly  to  the  hips.     In  a  person  of  average  height  it  is 

seventeen  inches  long,  three-quarters  of  an  inch  thick, 


FIG.  83.  —  A  SMALL  BIT  OF  THE  SPINAL 
COLUMN. 


282  PHYSIOLOGY   AND   HEALTH 

and  weighs  only  about  an  ounce ;  yet  in  that  ounce  of 
spinal  cord  most  rapid  and  delicate  work  is  done.  Like 
the  cerebrum,  it  consists  of  both  gray  and  white  matter, 
but  arranged  in  just  the  reverse  order,  i.e.  white  on  the 
outside  and  gray  within.  Like  the  cerebrum,  too,  it  is 
divided  by  a  deep  furrow  which  nearly  separates  it  into 
two  halves,  giving  it  the  appearance 
shown  in  Figure  83. 

This  figure  also  shows  the  gray 
matter  (in  shape  not  unlike  a  letter  H) 
sending  out  four  nerve  roots,  which 
soon  unite  to  make  a  pair  of  nerves, 
one  going  to  the  right  side  of  the  body, 
the  other  to  the  left.  There  are  thirty- 
one  pairs  of  nerves  given  off  by  this 
gray  matter,  and  these  nerves,  with  the 
twelve  pairs  of  cranial  nerves  (from 
the  brain  itself),  go  to  every  part  of 
the  body.  The  white  matter  of  the 
cord  takes  its  orders  from  the  gray 
matter,  and  like  the  nerves  it  does 
what  it  is  told  to  do,  as  any  well- 
trained  private  should.  The  white 
matter  is  really  simply  a  bundle  of 

FIG.  84. — A  NERVE.  n,  ,  N 

_,     .       ,       .    .        nerve  fibers  (axons). 

Showing    that    it    is    a  Vr  t      i       vi  i  -. 

bundle  of  fibers ;  also       Nerves.  —  Nerves   look    like   white 
a  single  fiber  more  threads,  some  very  tiny  and  some  as 

highly  magnified.  .        _,  ..    ,     . 

big  as  a  quill.  They  are  slightly  trans- 
parent and  soft  and  delicate.  Did  your  dentist  ever 
show  you  a  bit  of  a  dead  nerve  of  a  tooth  that  had 
been  giving  you  pain  before  he  destroyed  it?  It 


THE   GOVERNING  MECHANISM  283 

looks  like  a  useless  little  bit  of  white  marrow;  nothing 
suggests  that  it  is  of  any  importance.  The  microscope 
tells  a  very  different  story;  it  shows  that  the  nerves, 
after  they  leave  the  cord,  may  consist  of  thousands  of 
minute  threads  or  fibers  (axons  of  neurons)  too  small  to 
be  seen  without  a  microscope,  and  compactly  arranged 
in  bundles  (Figure  84).  .These  bundles  branch  as  they 
go  out  through  the  body,  the  smallest  parts  of  the  body 
finally  receiving  some  of  the  fibers.  The  number  of 
these  tiny  fibers,  running  from  the  brain  and  cord  over 
the  body,  literally  reaches  into  the  millions. 

Sensory  and  Motor  Nerves.  —  There  are  two  different 
kinds  of  nerve  fibers ;  they  may  go  through  the  body  in 
the  same  nerve  bundle,  but  they  always  work  separately, 
even  when  they  travel  side  by  side.  One  kind  is  always 
carrying  messages  to  the  cord  (and  perhaps  on  further  to 
the  brain) ;  the  other  kind  is  always  carrying  messages 
from  the  cord  (or  the  brain). 

The  nerve  fibers  that  carry  to  the  cord  (or  the  brain) 
news  of  what  is  happening  at  their  outer  ends  are  called 
sensory  nerves.  We  may  think  of  them  as  sentinels  or 
scouts  reporting  on  what  is  happening  at  the  advance 
line.  When  the  cord  or  the  brain  receives  a  report  from 
the  sensory  nerves  there  is  usually  something  to  be  done 
about  it.  The  nerves  that  carry  the  messages  to  the  brain 
have  nothing  to  do  with  this,  however ;  their  business  is  to 
make  reports,  not  to  carry  orders. 

From  these  reports  the^brain  or  the  cord  determines 
what  is  to  be  done,  and  the  orders  for  doing  it  are  carried 
by  the  motor  nerves,  which  transmit  these  directions  to 
the  muscles  with  which  they  are  connected.  These  motor 


284  PHYSIOLOGY   AND    HEALTH 

nerves  never  make  reports  about  what  is  going  on,  nor 
do  they  ever  cause  a  muscle  to  contract  until  they  receive 
orders  to  do  so.  Each  set  of  fibers  has  its  own  business 
and  never  is  known  to  try  to  attend  to  that  of  its  neighbor. 
Nerve  Trunks. --The  nerve  fibers  leave  the  cord  in 
two  branches  or  roots,  passing  through  a  swelling,  called 
a  ganglion  (see  Figure  83).  The  branch  at  the  back  of 
the  cord,  called  the  posterior  root,  carries  nervous  im- 
pulses ("  messages  ")  from  the  skin  or  other  organs  to 
the  cord  and  the  brain.  The  front  branch,  called  the 
anterior  root,  carries  nervous  impulses  from  the  brain 
to  the  muscles.  Beyond  the  ganglion  the  two  kinds  of 
nerves  unite  to  form  one  nerve  trunk,  in  which  the  sen- 
sory and  motor  nerves  run  side  by -side.  Both  kinds  of 
nerves  go  to  all  parts  of  the  body,  some  of  them  ever 
ready  to  tell  us  what  is  happening,  others  ready  to  make 
something  different  happen  by  telling  the  muscles  to  pull 
this  way  or  that.  The  two  kinds  of  nerves  look  so  much 
alike  that  one  could  never  tell  them  apart  by  their  ap- 
pearance ;  nor  can  one  see  how  they  work,  any  more  than 
one  can  tell  by  looking  at  a  telephone  wire  whether  or 
not  it  is  carrying  messages.  Like  the  telephone  wire  the 
nerves  never  look  busy. 

The  Sympathetic  System 

The  Work  of  the  Sympathetic  System.  —  There  is 
another  part  of  the  nervous  system,  closely  connected 
with  the  parts  described  and  yet  more  or  less  independent 
of  them.  Its  name,  the  sympathetic  system,  comes 
down  to  us  from  a  time  when  little  was  known  of  the 


THE  GOVERNING  MECHANISM 


285 


way  nerves  work ;  it  was  then  thought  that  this  set  of 
nerves  served  to  bring  into  harmony 
the  organs  of  the  body  that  are  dis- 
tant from  one  another.  Generally 
speaking,  the  sympathetic  system 
is  connected  with  the  organs  whose 
actions  are  involuntary,  while  volun- 
tary actions  are  controlled  by  the 
cerebro-spinal  system.  There  are 
exceptions  to  this  rule,  for  some  ac- 
tions of  the  brain,  which  belongs  to 
the  latter  system,  are  involuntary. 

The  sympathetic  system  consists 
of  two  long  nerve  cords,  or  chains 
of  nerve  ganglia,  one  lying  on  each 
side  of  the  backbone  and  in  the  back 
part  of  the  body  cavity  (Figure  85). 
The  two  cords  extend  from  the  skull 
to  the  end  of  the  spine.  From  the 
cords  are  given  off  many  small 
branches  which  go  into  the  organs 
of  the  abdomen,  into  the  glands, 
into  the  blood  vessels,  and  into  other 
parts  of  the  body  whose  actions  are 
involuntary. 

The    Solar    Plexus.  —  There    is 
part   of  the   sympathetic   sys- 


one 


tern  which  is  well  known;  it  is 
called  the  solar  plexus.  This  is  a 
great  mass  of  nerve  fibers,  mostly 
from  the  sympathetic  system,  that  form  a  very  com- 


FIG.  85.  —  THE  SPINAL, 
CORD  AND  SPINAL, 
NERVES. 

On  the  left  is  shown  the 
sympathetic  system. 
There  is  a  similar  sys- 
tem on  the  right  side  of 
the  cord,  not  shown  in 
the  figure. 


286  PHYSIOLOGY   AND   HEALTH 

plicated  network  back  of  the  stomach.  This  intricate 
mass  of  fibers  has  such  a  close  connection  with  most  of 
the  organs  in  the  abdomen  that  a  "'blow  upon  the  solar 
plexus  "  acts  directly  on  the  nerves  that  control  the 
vital  organs,  and  immediately  produces  tremendous 
physical  effects.  Such  a  blow  may  throw  the  body  entirely 
out  of  its  normal  condition  by  disarranging  the  stomach, 
the  heart,  and  the  breathing ;  it  even  disturbs  the  brain. 
The  close  connection  between  the  sympathetic  system 
and  the  cerebrum  is  also  shown  by  the  fact  that  one 
cannot  use  his  brain  when  he  is  "  sick  at  the  stomach." 
Moreover,  a  dog  cannot  digest  his  dinner  (neither  can  a 
person)  when  he  is  angry,  though  anger  has  to  do  with 
the  cerebrum,  while  digestion  is  connected  with  the  sympa- 
thetic system. 

The  Nervous  System  in  Action 

Cooperation  among  Neurons.  —  In  a  well-drilled  army 
the  soldiers  are  taught  to  act  together,  by  companies  or 
regiments,  since  by  this  means  much  more  can  be  accom- 
plished than  if  each  .soldier  acts  by  himself.  Our  neurons 
are  also  drilled  to  act  together.  When  a  boy  throws  a 
stone  he  does  not  realize  that  he  is  using  a  wonderful  ma- 
chine and  that  his  brain  is  sending  special  directions  to  over 
one  hundred  different  muscles  at  the  same  time.  If  his 
brain  neurons  should  make  a  mistake  and  cause  some  of 
the  muscles  to  contract  too  much  or  not  enough,  the  stone 
would  go  wide  of  the  mark.  It  is  not  strange,  therefore, 
that  it  takes  years  of  practice  before  a  baseball  pitcher  can 
control  his  muscles  so  accurately  that  he  can  make  the  ball 
go  where  he  wants  it  to  go,  or  strange  that  a  girl  must 


THE   GOVERNING  MECHANISM  287 

practice  a  long  time  before  she  can  so  direct  the  many 
muscles  of  her  arms  and  fingers  as  to  play  skillfully  upon 
the  piano.  During  all  this  time  it  is  not  so  much  the 
muscles  as  the  army  of  brain  neurons  that  is  being  taught, 
little  by  little,  how  to  send  such  orders  as  to  produce  the 
desired  results.  "  Practice  makes  perfect." 

Control  of  the  Neurons.  —  The  power  of  the  com- 
mander in  chief  (cerebrum)  to  control  the  neurons  is 
really  very  wonderful.  It  can  cause  a  single  muscle  to 
contract,  or  it  can  cause  many  muscles  to  act  together. 
The  brain  neurons  direct  many  of  the  voluntary  muscles 
without  any  attention  on  our  part ;  we  can,  however, 
take  charge  of  this  direction  by  simply  giving  it  our  atten- 
tion. For  instance,  a  man's  head  is  held  erect  by  keeping 
certain  of  the  neck  muscles  contracted,  but  he  is  not  usu- 
ally conscious  of  the  fact  that  his  brain  is  giving  orders  to 
the  neck  muscles.  If  he  gets  sleepy,  his  head  begins  to  drop 
over,  since  the  part  of  the  brain  that  controls  these  muscles 
is  beginning  to  take  a  rest ;  and  there  may  be  a  real 
struggle  between  his  will  to  keep  the  muscles  working  and 
the  demand  for  rest  made  by  the  neurons  that  control  them. 

Training  Neurons  to  Automatic  Action.  —  There  is  a 
limit  to  the  number  of  things  to  which  the  higher  neurons 
of  the  brain  can  give  attention  at  any  one  time.  If  the 
commanding  general  has  to  attend  closely  to  performing 
a  complicated  muscle  action,  he  cannot  do  much  thinking. 
Whenever  any  action  which  is  controlled  by  the  brain  can 
be  made  automatic,  i.e.  can  be  done  well  without  the 
conscious  action  of  the  higher  neurons,  then  these  higher 
ones  have  time  to  do  other  things.  Think  how  a  baby 
must  at  first  concentrate  his  attention  on  taking  each  step. 


288  PHYSIOLOGY   AND   HEALTH 

Afterwards,  however,  lie  walks  without  any  conscious 
effort  and  is  able  to  ask  a  constant  stream  of  questions 
as  he  runs  along  beside  you,  never  thinking  of  how  his 
feet  and  legs  must  move.  These  actions  are  still  con- 
trolled by  the  brain,  for  if  he  wishes  to  stop  and  look  at 
something,  he  can  stop ;  but  it  is  no  longer  necessary 
for  the  brain  to  direct  each  motion;  one  passes  into 
another  without  conscious  effort.  If  a  man  has  what 
is  called  a  ". well-trained  mind,"  the  actions  of  his 
neurons  are  to  a  very  large  extent  automatic. 

QUESTIONS 

1.  Why  must  the  body  have  a  general  to  command  it? 

2.  Describe  a  neuron  and  its  work ;  a  nerve  fiber. 

3.  Have  you  ever  seen  the  brains  of  a  calf  or  a  sheep?    If  so, 
describe  them. 

4.  If  a  person  is  paralyzed  in  his  right  arm,  is  the  trouble  in  the 
right  or  left  side  of  the  brain  ? 

5.  How  is  the  cerebrum  relieved  from  the  work  of  attending  to  the 
petty  details  of  bodily  action?    Why  is  this  an  advantage? 

6.  If  an  animal  were  deprived  of  his  cerebrum,  what  power  would 
he  lose  and  what  powers  would  he  retain? 

7.  Can  you  think  of  any  muscles  in  the  body  that  a  baseball 
pitcher  does  not  use  when  he  delivers  the  ball?    What  part  of  the 
brain  causes  the  muscles  which  he  uses  to  act  in  harmony? 

8.  Why  will  an  injury  to  the  medulla  cause  death  more  quickly 
than  an  injury  to  any  other  part  of  the  brain? 

9.  How  does  the  brain  get  its  knowledge  of  what  is  going  on  in 
the  toes  and  fingers? 

10.  Are  neurons  located  in  the  cortex  or  in  the  inner  part  of  the 
brain?     Where  are  they  located  in  the  spinal  cord? 

11.  What  would  be  the  effect  if  a  man's  spinal  cord  were  injured 
near  the  neck?     If  it  were  injured  near  the  waist  line? 

12.  What  organs  are  likely  to  be  disarranged  by  a  "blow  on  the 
solar  plexus"?    Why? 


CHAPTER  II 
INVOLUNTARY  AND  REFLEX  ACTIONS 

Voluntary  and  Involuntary  Actions.  —  In  controlling 
the  body,  the  nervous  system  acts  in  two  different  ways. 
Some  actions  are  voluntary;  we  are  able  to  make  them  at 
will.  These  come  wholly  from  the  cerebrum.  Others 
are  involuntary,  and  we  cannot  make  or  stop  them  by 
any  will  power;  we  may  even  be  unconscious  of  them, 
as  we  are  of  the  churning  motions  by  which  the  stomach 
mixes  the  food.  For  our  life  processes  the  involuntary 
actions  are  as  important,  if  not  more  important,  than  the 
voluntary  actions.  These  two  kinds  of  action  are  closely 
connected,  however,  for  an  action  that  is  at  first  voluntary 
may  later  come  to  be  carried  on  without  special  attention 
on  our  part  and  thus  become  partly  involuntary.  We  will 
first  consider  some  of  the  truly  involuntary  and  un- 
conscious actions. 

Involuntary  Actions 

Control  of  the  Heart  Beat.  —  In  the  case  of  certain 
animals  the  heart  will  continue  to  beat  when  entirely 
removed  from  the  body.  If  one  knows  how,  one  can 
keep  a  turtle's  heart  beating  for  days  after  it  has  been 
removed  from  the  body.  This  shows  that  the  heart 
(the  same  is  true  of  our  own  hearts)  can  beat  independ- 
ently of  any  orders  from  the  brain.  Its  action  may  be 

289 


290  PHYSIOLOGY   AND   HEALTH 

hastened  or  checked  by  the  brain,  however.  We  cannot 
intentionally  make  the  heart  beat  faster  or  slower,  but 
nevertheless  the  brain,  without  our  knowledge,  is  con- 
stantly doing  this. 

The  orders  that  the  brain  sends  out  to  the  heart  come 
partly  from  the  medulla  and  partly  from  the  sympathetic 
system.  One  pair  of  nerves  passes  from  the  medulla 
to  the  heart,  and  over  them  messages  are  constantly 
being  sent ;  another  pair  of  nerves  arises  in  the  sym- 
pathetic system,  and  these  nerves  carry  another  kind  of 
message.  A  boy  starts  to  run ;  he  needs  an  extra  amount 
of  blood  circulating  over  his  body.  Immediately  both 
sets  of  nerves  send  messages  to  the  heart,  causing  it  to 
beat  more  rapidly  and  the  blood  to  flow  faster.  After  the 
boy  has  stopped  running,  another  set  of  orders  go  to  the 
heart  which  cause  it  to  resume  gradually  its  ordinary  rate. 

Control  of  the  Blood  Vessels.  —  We  have  learned  that 
the  amount  of  blood  sent  to  each  part  of  the  body  is 
nicely  controlled  by  changes  in  the  size  of  the  small 
blood  vessels,  caused  by  muscle  fibers  that  pass  around 
them.  The  action  of  these  muscles  is  wholly  involuntary, 
but  they  are  acting  under  orders,  some  of  which  come 
from  the  medulla  and  some  from  the  spinal  cord  through 
the  sympathetic  nerves. 

That  part  of  the  body  which  is  most  actively  at  work 
needs  the  largest  increase  in  blood  supply,  since  the  blood 
brings  nourishment.  Sometimes  we  have  to  choose  as 
to  the  part  of  the  body  that  shall  have  all  the  blood  it 
asks  for.  The  football  captain,  for  instance,  if  he  is 
going  to  play  a  difficult  position  on  his  team,  one  that 
requires  much  running,  tackling,  etc.,  cannot  at  the  same 


INVOLUNTARY  AND   REFLEX  ACTIONS  291 

time  think  as  quickly  and  as  clearly  as  he  could  if  he  were 
simply  coaching  the  game.  That  is  not  because  he  gets 
confused,  but  for  the  simple  reason  that  he  is  using  so 
much  blood  in  his  muscles  that  there  is  not  enough  left 
for  the  best  brain  work.  Both  the  muscles  and  the  brain 
cannot  be  receiving  a  largely  increased  supply  of  blood 
at  the  same  time. 

Control  of  Breathing.  —  Our  breathing  is  largely  in- 
voluntary, since  it  'goes  on  all  the  time  whether  we  are 
thinking  of  it  or  not,  but  it  will  not  go  on  a  single  second 
if  the  nerves  that  pass  from  the  brain  to  the  breathing 
muscles  are  cut.  The  orders  to  breathe  come  from  a 
place  in  the  medulla  which  is  called  the  respiratory  center. 
We  can  slightly  modify  the  orders  by  our  will  power, 
but  just  as  soon  as  we  cease  to  pay  attention  to  them,  they 
will  go  in  their  usual  way. 

Control  of  the  Digestive  Functions.  —  The  churning 
motions  of  the  stomach,  the  motions  of  the  intestines  to 
force  the  food  along,  are  really  caused  by  commands 
from  the  nervous  system.  So,  too,  the  secretions  of  the 
various  glands,  the  salivary,  the  gastric,  the  pancreatic, 
and  indeed  all  others,  are  brought  about  by  messages  sent 
to  them  through  the  nerves  that  connect  them  with  the 
central  controlling  organ.  Much  of  this  kind  of  work  in 
the  digestive  process  is  brought  about  through  the  sympa- 
thetic system. 

Reflex  Actions 

Natural  Reflexes.  —  There  is  another  kind  of  half 
involuntary  action  called  reflex  action.  When  a  baby  is 
first  born,  it  can  do  certain  things,  such  as  winking  and 


292 


PHYSIOLOGY   AND   HEALTH 


sucking  its  thumb,  without  learning  how.  We  call 
these  actions  natural  reflexes.  The  baby  is  born  with 
plenty  of  neurons  which  have  nerve  fibers  leading  to 
skin,  to  muscles,  and  to  other  parts  of  his  body,  but  he 
can  make  little  use  of  them.  Long  before  he  can  move  a 
single  muscle  by  his  will  power  he  is  making  a  great  many 


Nerve 


FIG.  86.  —  Diagram  showing  (by  arrows)  the  track  of  a  nervous  impulse 
that  produces  reflex  action. 

complicated  motions.  In  his  skin  there  are  pain  spots, 
touch  spots,  cold  spots,  and  heat  spots.  Few  things  can 
happen  to  his  skin  without  arousing  one  or  more  of  these 
spots,  which  are  all  closely  connected  with  sensory 
nerves.  If  the  baby  lays  his  finger  on  a  pin  point,  some 
sensory  nerve  sends  a  report  of  it  to  the  neurons  in  the 
spinal  cord.  These  pass  the  report  on  to  other  neurons 


INVOLUNTARY  AND   REFLEX  ACTIONS  293 

to  which  are  attached  motor  fibers  having  control  of  those 
muscles  of  the  arm  which  move  the  finger,  thus  causing 
them  to  pull  the  finger  away  from  the  pin.  Figure  86 
shows  the  direction  taken  by  the  messages  in  a  reflex 
action. 

The  finger  can  be  pulled  away  in  a  fraction  of  a  second, 
and  this  will  happen  equally  well  whether  the  baby  is 
awake  or  asleep.  If  he  is  asleep,  he  will  probably  not 
feel  the  pin  prick  at  all ;  but  if  he  is  awake,  part  of  the 
message  will  go  on  to  the  neurons  in  the  brain,  and  give 
the  baby  a  sensation  of  pain.  This  he  feels,  however, 
some  time  after  the  reflex  action  of  the  cord  has  jerked 
the  hand  from  the  pin.  (You  see  he  does  not  pull  his 
finger  away  because  he  feels  the  pain ;  it  is  pulled  away 
before  there  is  any  pain.)  Probably  the  baby  begins 
to  cry,  his  experience  with  pin  pricks  not  being  sufficient 
to  tell  him  whether  this  one  is  serious  or  not ;  but  if  the 
same  thing  happened  to  his  big  brother,  the  pain  would 
hardly  be  noticed,  for  his  big  brother  knows  that  pin 
pricks  are  not  worth  attending  to  after  the  pin  is  removed. 

These  natural  reflexes,  or  instincts,  are  of  the  utmost 
importance  in  regulating  the  life  of  a  baby  before  he  has 
learned  to  do  anything  for  himself,  and,  in  fact,  through- 
out life  are  essential  to  one's  health,  safety,  and  comfort. 
If  a  grown  man  gave  all  of  his  attention  to  the  protection 
of  his  body  from  injury,  it  would  not  be  done  as  effec- 
tively as  it  is  done  by  the  unthinking  reflexes.  . 

How  Reflex  Action  Starts.  —  One  peculiarity  of  reflex 
actions  is  that  they  never  start  themselves.  The  neurons 
of  the  spinal  cord  do  not  pull  the  finger  away  from  contact 
with  a  lighted  candle  until  the  sensory  nerve  fibers  have 


294  PHYSIOLOGY   AND   HEALTH 

carried  a  report  to  the  cord.  On  receiving  that  report 
the  neurons  act  quickly ;  but  these  reflex  actions  are 
always,  as  in  this  case,  started  by  some  outside  stimulus, 
and  never  originate  within  the  neurons.  The  spinal  cord 
is  a  great  center  of  reflexes ;  the  medulla  is  also  largely 
a  reflex  organ.  Much  of  the  work  of  the  cerebellum  is 
also  done  by  reflex  action  and  there  are  reflex  centers  in 
the  cerebrum.  Reflexes  are  always  purposeful,  but  since 
they  do  not  depend  upon  our  wills  we  do  not  reason 
out  the  purpose  for  each  one.  Yet  they  all  have  a 
meaning  and  they  never  take  place  unless  there  is  some 
need  for  them. 

Training  the  Reflexes.  —  While  a  baby  can  perform 
certain  reflex  actions  as  well  as  any  one  else  can,  yet 
these  very  reflexes  may  be  made  more  effective  by  ex- 
perience. If  the  baby  saw  something  coming  toward 
one  of  his  eyes,  he  would  wink  instinctively,  regardless 
of  the  size  or  character  of  the  object.  The  grown  man 
would  be  likely  to  wink,  if  a  small  particle  were  seen  ap- 
proaching the  eye ;  to  turn  his  head,  if  a  flying  insect 
were  coming ;  to  put  his  hands  in  front  of  his  face,  if  the 
approaching  object  were  a  baseball.  All  these  different 
motions  would  be  as  truly  reflex  actions  as  the  baby's, 
but  they  are  "  educated  reflexes/'  based  upon  much  expe- 
rience with  the  outside  world. 

Value  of  Acquired  Reflexes.  —  There  is  another  form 
of  reflex  actions  called  acquired  reflexes.  They  are 
not  born  in  us  ;  we  have  to  learn  how  to  do  them.  The 
baby  is  born  with  such  natural  reflexes  as  the  ability 
to  wink  or  to  suck,  but  not  with  the  ability  to  walk.  At 
first  he  has  to  make  a  great  many  experiments  with  his 


INVOLUNTARY  AND  REFLEX  ACTIONS  295 

voluntary  muscles.  Later,  when  some  of  the  reflexes 
are  trained  to  the  new  task,  he  can  take  a  few  steps  to 
reach  his  mother's  arms.  His  big  brother  has  a  similar 
experience  when  he  learns  to  skate  or  to  swim,  and  his 
sister  when  she  learns  to  sew  or  to  play  on  the  piano. 
Reflexes  are  acquired  by  doing  a  thing  over  and  over, 
until  finally  the  different  motions  are  readily  made  with- 
out our  giving  attention  to  them. 

The  more  reflexes  we  can  acquire,  the  more  time  the 
mind  (the  general  in  command)  has  for  work  which  other 
parts  of  the  brain  cannot  do.  Therefore  it  is  obvious 
that  to  train  the  cerebellum  to  perform  complicated 
reflexes  badly  is  a  great  waste  of  energy  on  the  part  of 
both  cerebrum  and  cerebellum.  For  instance,  the  cerebel- 
lum can  in  time  acquire  great  facility  in  making  the  com- 
plicated combinations  of  movements  necessary  in  play- 
ing the  organ ;  but  if  one  learns  to  make  the  movements 
heedlessly,  sometimes  doing  them  right,  more  often 
wrong,  he  will  never  make  a  good  organist.  So  while 
our  voluntary  actions  are  gradually  becoming  reflex 
actions,  we  ought  to  insist  on  doing  them  perfectly,  for 
in  this  way  only  will  our  reflexes  become  well-trained 
servants.  When  the  organist  can  play  correctly  without 
paying  attention  to  his  fingers,  or  to  his  feet,  he  is  free 
to  think  about  the  feelings  and  thought  suggested  by  the 
music  and  to  try  to  interpret  them  for  those  who  are 
listening. 

Reflex  and  Voluntary  Actions.  —  The  essential  differ- 
ence between  reflex  and  voluntary  actions  may  be  made 
more  clear  by  giving  very  briefly  the  result  of  experi- 
ments that  have  been  made  with  normal  frogs  and  with 


296  PHYSIOLOGY   AND    HEALTH 

frogs  whose  brains  have  been  removed,  called  for  con- 
venience "  reflex  frogs."  If  the  hind  leg  of  such  a  frog 
were  slightly  pinched,  the  experimenter  could  tell  exactly 
what  the  reflex  frog  would  do  —  it  would  jerk  its  leg 
away.  The  normal  frog  might  jerk  its  leg  away  or  it 
might  decide  to  jump  out  of  reach.  It  might  even  de- 
cide, by  act  of  will,  to  pay  no  attention  at  all.  The  reflex 
frog  would  act  upon  the  outside  stimulus,  but  that 
stimulus  (in  this  case  the  pinching  of  the  foot)  would  be 
only  one  of  the  factors  that  would  enter  into  the  action 
taken  by  the  normal  frog.  So  it  is  evident  that  purely 
reflex  actions  are  quickly  made  and  are  not  subject  to 
caprice,  but  can  be  determined  in  advance,  provided  that 
they  are  not  hampered  or  interfered  with. 

Sensations  Connected  with  Reflexes.  —  Sensation  is 
not  necessary  to  reflex  action.  If  the  message  sent  to  the 
spinal  cord  is  acted  upon  without  going  through  to  the 
brain,  there  will  be  no  sensation,  since  sensations  are 
felt  in  the  brain  only.  If  you  drop  a  bit  of  blazing  sealing 
wax  on  your  finger,  the  sensation  of  pain  seems  to  be  in 
the  finger,  but  there  is  no  pain  felt  until  the  message  that 
starts  in  the  finger  reaches  the  brain  and  is  there  inter- 
preted as  pain.  There  would  be  no  pain  if  the  nerve 
that  goes  from  the  finger  to  the  brain  were  so  cut  that  the 
message  could  not  get  through  to  the  brain.  In  that 
case  you  would  feel  no  pain  at  all,  even  though  the  blazing 
wax  went  burning  into  your  flesh.  When  the  brain  feels 
pain,  it  locates  the  pain  at  the  end  of  the  nerve  that 
brought  the  message.  Sometimes  the  brain  makes  a 
mistake ;  if  the  nerve  from  the  finger  to  the  brain  were 
injured  at  the  elbow,  the  message  telling  of  the  injury 


INVOLUNTARY  AND   REFLEX  ACTIONS  297 

would  cause  pain  when  it  reached  the  brain,  but  the  brain, 
recognizing  the  message  as  coming  from  a  finger  nerve, 
would  locate  the  pain  in  the  finger  where  there  was  really 
no  trouble  at  all. 

It  is  evident  now  how  reflex  action  may  take  place  when 
a  person  is  asleep,  since  the  message  has  to  go  only  to  the 
spinal  cord  and  from  there  back  to  the  muscles,  without 
entering  the  brain.  Further  proof  that  reflexes  act 
independently  of  the  brain  is  given  by  the  fact,  already 
mentioned,  that  they  take  place  perfectly  in  animals  whose 
brains  have  been  removed. 

Voluntary  Actions 

Most  of  our  conscious  actions  we  bring  about  by  defi- 
nite intention.  Such  actions  we  call  voluntary  actions. 
Only  a  few  of  these  actions  are  possible  to  a  new-born 
baby,  who  lives  mostly  by  instinct.  Very  soon,  however, 
he  begins  to  learn  that  he  can  do  some  things  inten- 
tionally, and  then  week  after  week  and  year  after  year 
his  voluntary  actions  become  more  and  more  important, 
as  he  trains  his  numerous  neurons  to  do  his  bidding. 

The  Training  of  Neurons.  —  The  brain,  like  the  army, 
becomes  more  efficient  the  better  it  is  trained.  The 
training  of  our  neurons  started  long  before  we  ever  heard 
of  them.  This  will  be  clear  if  you  will  watch  a  baby  as 
he  learns  to  use  his  muscles  and  his  senses.  Think  of 
what  you  see  him  doing.  All  day  long  he  kicks  his  legs 
and  moves  his  arms,  at  first  in  a  seemingly  aimless  way ; 
but  if  you  realize  that  by  these  awkward  motions  he  is 
getting  his  neurons  into  training,  maybe  you  will  not  wish 
him  to  be  less  active. 


298  PHYSIOLOGY   AND   HEALTH 

When  you  were  old  enough  to  play  games  you  began  a 
new  kind  of  training,  and  it  was  all  the  more  valuable 
because  you  delighted  in  the  games  and  did  not  know  that 
they  were  serving  any  purpose  except  to  give  you  pleas- 
ure. Yet  all  the  time  they  were  developing  the  neurons 
that  control  the  muscles  and  those  through  which  the 
will  and  the  senses  work,  teaching  those  used  when  we 
think  to  think  quickly  and  to  make  quick  and  accurate 
judgments. 

More  Advanced  Training.  —  By  and  by  you  were  old 
enough  to  go  to  school,  and  then  began  a  different  form 
of  training  the  neurons.  You  had  been  learning  to  do 
things  because  you  wished  to  do  them ;  you  wished  to  play 
well  the  games  that  you  saw  other  children  playing,  you 
wished  to  learn  to  do  things  about  the  home  because  you 
found  that  it  gave  your  parents  pleasure  when  you  did 
them. 

At  school  it  was  all  different ;  you  were  told  to  do 
certain  kinds  of  work.  There  was  no  game  about  it,  and 
maybe  you  saw  no  pleasure  in  it  either  for  others  or  for 
yourself.  The  simple  fact  is  that  the  neurons  were  ready 
for  a  different  kind  of  training ;  the  new  things  given  you 
to  do  were  really  no  harder  than  what  you  had  to  do  as  a 
baby.  It  is  no  harder  to  learn  to  read  than  it  was,  when 
you  were  a  baby,  to  learn  the  meaning  of  countless 
messages  that  were  being  sent  to  the  brain  from  your 
eyes. 

Neurons  not  Trained  by  Spurts.  —  A  listless  pupil  al- 
ways imagines  that  if  the  time  should  come  when  he  wishes 
to  study,  or  if  the  subject  should  be  interesting,  he  could 
do  as  good  work  as  any  one  in  his  class.  That  is  a 


INVOLUNTARY  AND   REFLEX  ACTIONS  299 

very  grave  mistake.  He  knows  well  enough  that  he 
cannot  keep  his  arm  in  a  sling  all  winter  and  then  pitch 
baseball  fast  and  accurately  when  spring  comes.  Neither 
the  pitching  muscles  nor  the  neurons  that  control  them 
would  be  fit  to  work.  That  is  just  as  true  of  the  neurons 
that  he  ought  to  use  when  he  studies ;  they,  too,  have  to 
be  exercised  constantly.  He  cannot  call  upon  them  for 
a  sudden  spurt  of  work  unless  he  has  prepared  them  for 
it ;  he  only  deceives  himself  when  he  imagines  that  when- 
ever he  feels  like  it  he  can  make  up  for  lost  time. 

The  boy  who  studies  with  a  will  has  much  more  time 
to  give  to  his  other  interests  than  the  boy  who  is  always 
behind  with  his  lessons,  because  he  thinks  about  doing  them 
instead  of  about  getting  them  done.  Remember  that 
the  habit  of  "  dawdling  "  over  work  will  follow  you  and 
that  you  will  take  into  the  high  school  with  you  the  very 
neurons  that  you  train  or  fail  to  train  in  your  grammar 
school  work.  Even  then  it  will  not  be  too  late  to  teach 
them,  but  you  will  have  to  work  much  harder  to  get  the 
same  result,  for  you  have  already  trained  them  in  one 
direction,  and  thus  have  formed  for  them  what  are  called 
"  habits." 

Good  and  Bad  Habits.  —  "  Bad  habits  "  are  always  a 
hindrance  to  us,  while  "  good  habits  "  are  of  the  greatest 
help.  Much  of  our  education  is  designed  to  give  us  good 
habits  in  speaking,  in  hearing  correctly,  in  telling  a  story 
truthfully,  in  thinking,  in  walking,  in  doing  the  many 
actions  required  by  our  daily  lives.  Habits  are  formed  by 
repetition.  Could  you  write  a  sentence  the  first  time  you 
tried  ?  Do  you  remember  how  hard  it  was  to  hold  your 
fingers  right,  how  the  pen  would  not  stay  where  you 


300  PHYSIOLOGY   AND   HEALTH 

wanted  it?  You  kept  on  trying  to  write  over  and  over 
again  until  the  time  came  when  you  did  not  have  to  think 
of  your  fingers  or  of  the  letters  they  were  to  make ;  you 
just  willed  (the  work  of  the  cerebrum)  to  write  a  certain 
word  and  left  the  rest  to  the  faithful  action  of  the  group 
of  neurons  that  you  had  trained  to  direct  the  muscles 
used  in  the  writing.  Well-trained  neurons  are  of  the 
greatest  help  to  the  thinking  part  of  the  brain,  relieving 
it  of  much  routine  work  and  giving  it  time  to  learn  things 
that  we  want  to  know. 

Neurons  Deserve  Good  Training.  —  One  of  the  worst 
things  about  a  bad  habit  is  that  it  might  just  as  well  have 
been  a  good  or  useful  habit ;  the  neurons  that  have  been 
allowed  to  do  their  work  badly  could  just  as  well  have 
been  trained  to  do  it  properly.  It  is  well  worth  our  while 
to  take  the  trouble  to  teach  these  neuron  soldiers  of  ours 
to  work  properly,  for  they  are  faithful  and  untiring,  and 
once  taught  they  will  continue  for  a  lifetime  to  act  as 
we  have  trained  them. 

Habits  may  be  described  as  acquired  reflex  actions, 
and  like  all  such  reflexes,  when  once  acquired,  they  may 
be  improved.  At  first  one  finds  it  difficult  to  do  any 
little  act,  like  rising  to  one's  feet  when  an  older  person 
enters  the  room ;  by  and  by  it  becomes  easier  and  in- 
voluntary. One  never  forgets  then,  but  rises  without 
thinking,  and  with  more  real  consideration,  until  finally 
he  would  feel  uncomfortable  if  he  failed  in  this  act  of 
courtesy.  We  have  made  a  distinct  gain  whenever  we 
train  a  set  of  neurons  to  do  automatically  something  that 
before  had  to  be  done  by  the  expenditure  of  conscious 
effort, 


INVOLUNTARY  AND   REFLEX  ACTIONS  301 

QUESTIONS 

1.  Explain   the   difference   between   voluntary   and   involuntary 
action.     Which  controls  the  flow  of  saliva  when  we  taste  food?     The 
flushing  of  the  face  when  one  is  embarrassed?     The  motions  of  an 
artist  in  painting  a  picture? 

2.  When  a  boy  starts  to  run,  what  changes  take  place  in  his  cir- 
culation and  what  controls  these  changes  ? 

3.  Explain  why,  when  a  barefooted  boy  steps  on  a  sharp  stone, 
he  jumps  before  he  actually  feels  the  pain. 

4.  Can  you  mention  any  natural  reflexes   (instincts)   which  a 
newly-hatched  chicken  possesses? 

5.  What  natural  reflex  movement  occurs  when  a  bit  of  food  gets 
into  the  windpipe?    Name  as  many  more  natural  reflex  movements 
as  you  can  think  of. 

6.  What  happens  if  you  tickle  the  foot  of  a  sleeping  person? 
Was  he  conscious  of  the  tickling?     Explain  your  answer. 

7.  Mention  several  reflex  actions  that  you  have  acquired. 

8.  Why  is  one  unable  to  ride  a  bicycle,  row  a  boat,  or  swim  per- 
fectly, the  first  time  he  tries  ? 

9.  What  effect  would  it  have  on  your  progress  at  school,  if  you 
had  to  think  about  each  movement  every  time  you  walked  about  or 
changed  your  position,  or  did  any  writing?     Why  is  it  better  to  per- 
form ordinary  actions  by  reflex  action  rather  than  by  conscious  atten- 
tion? 

10.  Has  the  playing  of  games  any  real  value  to  a  boy  or  girl?    Ex- 
plain.    Can  you  see  any  reason  why  boys  and  girls  do  not  like  the 
same  kinds  of  plays? 

11.  What  is  gained  by  training  our  neurons  to  reflex  action  early  in 
life? 

12.  What  are  habits?    How  are  habits  formed?  .  Is  it  harder  to 
form  good  habits  than  bad  ones  ? 

13.  How  do  the  bones  and  muscles  of  the  shoulders  get  the  habits 
which  make  a  person  round-shouldered?     In  what  way  might  the 
same  bones  and  muscles  have  formed  other  habits  ? 

14.  What  is -the  meaning  of  the  saying,  "You  can't  teach  an  old 
dog  new  tricks"? 


CHAPTER   III 
BETTER   GOVERNMENT   OF  THE  BODY 

How  the  Mind  Works 

The  Mind  Works  through  the  Cerebrum.  —  The  com- 
mander in  chief  of  our  army  of  neurons  we  call  the  mind ; 
this  is  the  part  that  thinks,  that  feels,  and  that  wills. 
We  do  not  know  much  about  how  the  mind  uses  the  rest 
of  the  nervous  system,  nor  just  what  the  mind  is,  but  we 
do  know  that  it  works  through  the  cerebrum.  There 
are  many  interesting  facts  that  show  this.  If  a  clot  of 
blood  forms  on  the  brain,  it  produces  various  mental 
disturbances,  sometimes  causing  the  person  to  lose  his 
mind  entirely  for  a  while.  These  troubles  pass  away  when 
the  clot  is  absorbed.  There  have  been  accidents  which 
have  broken  away  part  of  the  skull  so  that  the  brain  could 
be  seen.  Scientists  who  have  carefully  watched  the  ex- 
posed brain  have  found  that  when  the  patient  goes  to 
sleep  and  becomes  unconscious,  very  little  blood  goes  to 
the  brain,  but  that  as  soon  as  he  wakes  the  blood  flows 
there  rapidly.  If  he  thinks  hard,  a  very  large  supply  of 
blood  goes  to  the  brain.  All  this  shows  that  the  brain 
works  when  we  think. 

So  students  have  concluded  that  the  mind  does  different 
kinds  of  work  in  different  parts  of  the  brain.  This  theory 
has  been  tested  in  many  ways.  Sometimes  a  certain 
part  of  the  brain  may  be  injured  by  a  fall  or  a  blow. 

302 


BETTER  GOVERNMENT  OF  THE  BODY 


303 


This  causes  some  special  effect  upon  the  mind.  For  ex- 
ample, injury  to  one  part  of  the  brain  injures  or  de- 
stroys the  power  of  hearing,  while  injury  at  another 
place  interferes  with  vision.  By  comparing  many  such 
cases  it  has  been  possible  to  determine  the  particular 
parts  of  the  brain  with  which  hearing  and  seeing  and 
many  other  mental  actions 
are  connected.  Figure 
87  will  give  some  idea  of 
the  results  of  these  dis- 
coveries, for  it  shows  what 
kind  of  actions  are  asso- 
ciated with  the  different 
parts  of  the  cerebrum. 

Memory.  —  There  does 
not  seem,  at  first  thought, 
to  be  any  connection  be- 
tween memory  and  the 
neurons.  You  learn  a 
song  to-day  and  perhaps 
years  from  now  something 
reminds  you  of  it.  You 
may  recall  a  part  of  the 
tune  or  a  line  of  the  words,  and  with  whatever  clew  you 
have  you  begin  searching  your  memory,  trying  to  find 
the  rest  of  the  song.  Where  is  it  ? 

The  simplest  answer  seems  to  be  that  it  is  stored  up 
in  some  group  of  neurons.  You  can  find  it  again  if  you 
succeed  in  calling  upon  the  right  group.  We  may  perhaps 
think  of  the  neurons  that  are  trying  to  bring  back. the 
song  as  actually  sending  out  one  message  after  another 


FIG.  87.  —  THE  BRAIN  IN  POSITION  IN 

THE  SKULL,. 

Showing  the  location  of  some  of  the  chief 
functions  of  the  cerebrum. 


304  PHYSIOLOGY   AND   HEALTH 

through  all  their  many  branches,  in  their  efforts  to  locate 
the  ones  that  have  retained  the  song  (remember  that 
there  are  9,000,000,000  of  them).  The  situation  would 
be  different  if  you  had  been  in  the  habit  of  singing  that 
song  frequently.  Then  there  would  be  no  difficulty  in 
getting  the  message  of  the  proper  neurons ;  the  path  to 
them  would  be  well  known. 

Memory  depends  also  upon  the  distinctness  of  the  im- 
pression made  upon  the  neurons.  Listless,  half-hearted 
attention  to  one's  lessons,  when  one's  mind  is  on  a  ball 
game  perhaps,  has  much  the  same  result  as  writing  on 
a  sheet  of  paper  with  a  pen  that  carries  no  ink. 

Reasoning.  —  Memory  is  not  confined  to  men,  as 
animals  have  a  clear  memory  of  certain  things.  Many  a 
man  traveling  on  an  exposed  and  lonely  road  prefers  to 
trust  his  life  to  his  horse's  memory  of  the  turns  rather 
than  to  trust  his  own.  Reasoning,  however,  appears  to  be 
almost,  if  not  wholly,  beyond  the  capacity  of  the  neurons 
of  the  animal's  brain.  Many  tests  have  been  made 
with  the  animals  that  are  nearest  to  man,  comparing 
their  mental  powers  with  the  mental  powers  shown  in 
the  lowest  types  of  mankind.  A  striking  difference  is 
noticeable.  An  intelligent  chimpanzee  and  a  low  type  of 
savage  were  once  shut  up  in  huts.  The  only  opening  in 
each  was  fastened  by  a  lock  that  could  be  released  only 
by  pulling  out  a  pin  that  was  placed  perpendicularly  in 
the  lock.  Both  wanted  to  get  out,  both  worked  hard  to 
find  out  how  they  could  undo  that  strange  kind  of  fasten- 
ing, and  both  succeeded  in  discovering  that  by  removing 
the.  pin  the  door  would  open.  The  lock  was  then  re- 
arranged so  that  it  would  work  only  when  the  pin  was 


BETTER  GOVERNMENT  OF  THE  BODY     305 

placed  horizontally.  Both  the  savage  and  the  chimpan- 
zee were  again  shut  up  in  their  huts.  The  savage  rec- 
ognized the  pin  in  its  new  position  and  quickly  released 
himself,  but  the  chimpanzee  had  to  start  all  over  again 
with  his  efforts  to  undo  the  lock,  fumbling  and  trying  as 
though  he  had  never  experienced  such  a  lock  before. 

The  chimpanzee  can  remember  as  clearly  as  we  do  the 
people  whom  he  likes  or  dislikes,  but  he  shows  little  if 
any  evidence  that  he  is  able  to  reason  about  his  feelings 
or  to  decide  to  control  them. 

The  Care  of  the  Mind 

Brain  Work  and  Fatigue.  —  It  is  known  that  neurons 
grow  stronger  with  use.  There  is  no  reason  why  people 
should  fear  the  result  of  hard  brain  work,  if  only  they 
would  use  as  much  common  sense  about  it  as  they  would 
use  in  the  care  and  training  of  a  hunting  dog  or  a  work- 
horse or  any  other  animal  that  had  hard  work  to  do  for 
them.  We  do  not  need  to  search  for  brain  foods  or  to 
take  alarm  lest  each  slight  headache  means  that  the 
brain  is  being  overtaxed. 

When  a  man  is  carrying  a  heavy  package,  he  "  changes 
hands  "  occasionally,  knowing  that  in  this  way  he  can 
carry  the  load  farther  and  with  less  fatigue.  A  similar 
advantage  is  gained  by  alternating  exercise  and  brain 
work;  they  are  different  methods  of  using  the  neurons, 
and  to  a  large  extent  different  groups  of  neurons  are  em- 
ployed in  the  two  kinds  of  work.  So  the  groups  that  are 
used  for  brain  work  have  a  chance  to  rest  "while  those 
which  direct  the  work  of  the  muscles  are  active.  But 
suppose  that  the  man  with  the  package  were  to  carry  it 


306  PHYSIOLOGY  AND   HEALTH 

in  his  right  hand  as  long  as  he  could  possibly  hold  it, 
and  then,  after  his  right  arm  was  absolutely  tired  out,  were 
to  change  the  package  over  to  the  left  hand.  What  would 
happen  ?  He  would  find  (and  this  can  be  readily  tested 
by  any  pupil)  that  his  left  hand  and  arm  instead  of  being 
fresh  and  strong  were  tired  at  the  start,  because  of  the 
fatigue  poisons  that  had  been  produced  by  the  severe 
overstrain  of  the  other  arm. 

It  has  been  proved  that  the  same  thing  happens  with 
the  groups  of  neurons.  "  Fatigue  "  experiments  are  con- 
stantly being  made  in  laboratories  to  demonstrate  the 
relation  between  brain  "  fag "  and  muscle  "  fag." 
They  show  that  a  man  can  do  a  certain  amount  of  work 
with  a  single  set  of  muscles  the  first  thing  in  the  morning, 
and  that  after  an  hour  of  study  he  can  again  do  just  about 
the  same  amount  of  muscle  work.  But  let  him  study 
hard  for  five  hours  on  a  stretch  and  then  test  the  ability 
of  his  muscles  to  pull  a  weight.  Even  though  during 
these  five  hours  neither  the  muscles  nor  the  neurons  that 
control  the  muscles  have  been  working,  yet  he  finds  that 
they  will  not  work  well  no  matter  how  hard  he  tries.  The 
fact  is,  they  share  in  the  overfatigue  of  the  other  neurons 
of  the  cerebrum.  The  only  way  to  make  them  fit  for 
work  again  is  to  sleep,  or  to  take  time  for  a  complete  rest. 

Concentration.  -  -  This  is  a  hard  sounding  word,  and 
suggests  a  disagreeable  amount  of  effort ;  but  just  watch 
a  boy  enthusiast  at  a  football  game.  He  is  enjoying  him- 
self every  moment  of  the  time;  his  entire  interest  is 
fixed  on  the  play ;  yet  he  would  probably  think  you  were 
making  fun  of  him  if  you  were  to  tell  him  that  he  was  an 
excellent  example  of  concentration. 


BETTER  GOVERNMENT  OF  THE  BODY     307 

The  secret  of  concentration  is  interest.  When  we  are 
thoroughly  interested  in  a  subject,  it  is  only  natural  to 
turn  our  whole  attention  to  it ;  and  the  result  is  that  we 
learn  more  about  it  and  enjoy  it  more  thoroughly  than 
we  could  in  any  other  way.  Take  a  hard  case :  a  boy 
has  some  difficult  problems  in  percentage  to  do ;  he  does 
not  like  arithmetic  very  well,  and  percentage  seems  to 
him  the  dullest  of  all  its  topics.  How  can  he  concen- 
trate his  mind  on  the  problems  ?  This  much  is  evident : 
the  shorter  time  he  takes  to  do  them  the  less  they  will 
annoy  him ;  the  sooner  he  completes  the  whole  topic  of 
percentage,  the  sooner  he  finishes  his  book  in  arithmetic, 
the  sooner  he  will  be  free  from  what  is  to  him  drudgery. 
So  his  desire  to  solve  those  problems  and  be  free  to  do 
something  he  likes  to  do  ought  to  enable  him  by  his  will 
power  to  fix  his  entire  attention  on  them;  then  they 
can  be  completed  in  one  quarter  the  time  that  they  might 
otherwise  take. 

The  ability  to  think  of  one  thing  at  a  time  is  very  largely 
a  habit  and  one  of  the  habits  that  must  be  acquired  by 
everybody  who  wants  to  do  good  work.  Wandering 
attention  does  not  make  for  success  in  any  line  of  work, 
nor  is  there  enjoyment  in  work  done  in  that  way.  Un- 
fortunately the  habit  of  letting  the  mind  wander  is  easily 
acquired  by  those  who  do  not  take  the  trouble  to  acquire 
the  habit  of  concentration.  Which  of  these  two  habits 
are  you  forming? 

Recreation.  —  The  mind  needs  recreation,  especially 
recreation  taken  with  the  sort  of  enthusiastic  interest 
that  the  boy  in  our  illustration  gave  to  the  football  game. 
If  he  had  spent  the  afternoon  at  that  game  with  no  interest 


308  PHYSIOLOGY  AND   HEALTH 

either  in  the  game  itself  or  in  the  players,  just  taking  it 
in  as  a  means  of  "  killing  time/'  he  would  get  little  or  no 
recreation.  Everybody  needs  to  discover  some  form  of 
recreation  for  which  he  has  time  and  opportunity.  It 
should  be  something  that  he  likes  to  do.  The  mention 
of  a  few  possibilities  for  the  boy  and  the  girl  will  suggest 
how  many  others  there  are  to  be  considered  —  stamp 
collecting,  training  pets,  making  pieces  of  furniture, 
skating,  swimming,  climbing,  gardening,  knitting,  em- 
broidery, fine  cooking,  fine  sewing,  house  decorating, 
candy  making. 

The  form  of  recreation  chosen  matters  little,  provided 
that  it  is  something  we  delight  in  doing  and  provided, 
further,  that  we  do  it  with  energy  and  enthusiasm.  To 
be  indolent  or  negative  or  half-hearted  about  our  rec- 
reation changes  it  at  once  from  good  play  into  poor  work". 
You  have  seen  boys  who  go  onto  the  athletic  field  or  into 
a  gymnasium  and  stand  around,  first  on  one  foot  and  then 
on  the  other,  watching  those  who  are  taking  part  in  the 
games.  They  may  take  part  for  a  few  minutes  in  some- 
thing  that  looks  easy,  but  they  are  usually  just  waiting 
for  something  else  to  happen.  They  are  not  getting  rec- 
reation, for  they  are  not  doing  anything  positively  and 
with  satisfaction. 

How  to  Rest.  —  Partial  rest  comes  from  change  of 
work  (if  the  change  is  made  before  one  is  too  weary), 
and  especially  from  work  interspersed  with  recreation. 
Complete  rest  comes  from  sleep  and  absolute  inactivity. 
The  student  does  not  progress  according  to  the  amount 
of  time  that  he  spends  over  his  books,  but  according  to  the 
amount  of  work  he  does  upon  them.  When  his  mind  is 


BETTER  GOVERNMENT   OF  THE  BODY  309 

alert  and  attentive,  he  can  accomplish  more  in  half  an  hour 
than  he  can  in  an  hour  of  listless  work  when  his  brain  is 
tired.  A  half  hour  given  to  complete  rest  in  the  middle 
of  the  day  may  enable  him  to  master  his  lessons  more 
quickly  and  more  thoroughly  than  if  he  had  studied 
that  half  hour. 

When  Things  Go  Wrong.  —  Everybody  has  days  when 
nothing  seems  interesting,- neither  work  nor  play, — when 
everything  seems  to  go  wrong.  This  usually  means  that 
one  has  eaten  too  much  or  slept  too  little.  When  some 
mistake  of  that  sort  has  robbed  us,  for  the  time  being, 
of  the  interest  and  joy  we  ought  to  have  in  work,  the  only 
thing  to  do  is  to  "  borrow  "  some  from  the  future ;  that 
is  the  only  kind  of  borrowing  that  makes  one  rich.  So 
borrow  a  happy  face ;  meet  every  difficulty  with  a  laugh, 
no  matter  if  you  do  feel  more  like  crying ;  undertake  your 
tasks  with  courage,  and  before  you  know  it  things  will 
begin  to  go  right  again. 

Sleep  the  Restorer  of  Neurons.  —  An  exhausted  neuron 
has  its  own  way  of  showing  its  fatigue,  but  it  takes  a 
microscope  to  see  the  change.  When  greatly  fatigued, 
the  nucleus  of  the  neuron  shrinks  and  begins  to  look 
crumpled  and  ragged.  After  a  good  night's  sleep  it  be- 
comes firm  and  clear  again. 

When  an  athlete  is  preparing  for  a  race  or  when  a 
scholar  is  preparing  for  an  examination,  he  needs  to  be 
ready  when  the  time  comes  to  do  his  very  best  work. 
The  athlete  goes  to  bed  early ;  the  scholar  frequently  sits 
up  late  studying.  Which  takes  the  more  sensible  course  ? 
Every  trainer  knows  that  the  man  who  has  not  slept  the 
night  before  has  no  chance  at  all  in  a  rowing  match,  even 


310  PHYSIOLOGY   AND   HEALTH 

with  an  inferior  opponent ;  the  issue  between  them  is  soon 
decided  beyond  all  doubt.  But  this  is  not  so  readily 
appreciated  by  the  student. 

Sometimes  boys  and  girls  take  pride  in  studying  far 
into  the  night.  They  find  much  work  that  could  be  re- 
viewed with  profit,  and  they  may  be  convinced  that  on 
this  one  occasion  they  need  to  study  until  midnight. 
That  feeling  may  be  well  founded.  They  may  need  to 
know  many  things  that  they  have  neglected  to  learn, 
but  it  is  too  late  to  learn  them.  To  try  to  prepare  for  a 
test  in  that  way  is  a  most  absurd  blunder,  because  what 
one  tries  to  learn  under  such  conditions  makes  very 
little  impression  on  tired  neurons.  Many  facts  may  be 
crammed  into  one's  head  by  such  midnight  study ;  but 
when  morning  comes,  they  are  usually  no  longer  there. 
The  result  of  our  night's  work  has  been  only  a  tired  brain, 
which  unfits  us  to  acquit  ourselves  as  well  as  we  otherwise 
might. 

Habits  of  Sleep.  —  In  ways  of  which  we  are  totally 
unconscious  the  body  adapts  itself  to  regular  hours  for 
stated  duties,  and  works  with  much  greater  ease  and 
accuracy  when  we  are  systematic.  Regular  habits  of  sleep 
are  as  desirable  as  regular  habits  of  eating.  Children  are 
sometimes  glad  when  they  "  outgrow  "  a  regular  hour  for 
bedtime ;  but.  the  fact  is  that  grown  men  and  women  would 
feel  better  and  work  more  successfully  if  they  would  go 
to  bed  at  the  same  hour  every  night.  Many  cases  of 
habitual  wakefulness  might  have  been  prevented  by  the 
formation  of  such  a  habit.  Young  people  are  seldom 
troubled  about  getting  to  sleep.  Five  minutes  after  one 
gets  into  bed  one  should  be  asleep,  and  that  five  minutes 


BETTER  GOVERNMENT  OF  THE  BODY     311 

ought  to  be  kept  free  from  thoughts  about  work  or  worries. 
It  is  very  easy  to  form  the  habit  of  thinking,  the  last 
thing  every  night,  of  something  very  pleasant ;  that  helps 
to  insure  sound  sleep  and  a  happy  waking. 

Few  persons  sleep  too  much,  many  sleep  too  little. 
Grown  people  need  to  sleep  from  seven  to  nine  hours ; 
children  from  ten  to  twelve;  babies  from  sixteen  to 
twenty.  So  much  depends  upon  the  individual  and  his 
work  that  no  fixed  rule  can  be  made  for  all.  If  one  forms 
the  habit  of  going  to  sleep  quickly  and  of  getting  up  in- 
stantly on  waking,  there  is  little  danger  that  he  will 
take  more  sleep  than  he  requires.  There  is  much  wisdom 
in  the  quaint  old  saying,  "  When  you  wake,  jump  out  of 
bed  as  though  the  bed  were  on  fire." 

A  Sound  Mind  in  a  Sound  Body. — Mind  and  body  are 
so  closely  related  that  it  is  useless  to  try  to  train  the  mind 
to  do  its  best  if  one  neglects  to  keep  the  body  vigorous. 
To  be  sure,  the  mind  can  rise  above  many  physical  ail- 
ments, forgetting  and  ignoring  them  as  it  works.  That 
it  should  be  made  to  do ;  but  we  are  deluding  ourselves 
if  we  imagine  that  our  minds  work  as  well  under  those 
circumstances  as  when  we  are  in  good  physical  condition. 
Those  who  enjoy  books  and  study  should  be  especially 
careful  to  keep  themselves  in  good  health.  Recreation, 
exercise,  wholesome  food,  fresh  air,  and  sunshine  must  be 
sought  by  the  student  who  is  eager  to  excel  in  any  kind 
of  mental  work.  Rightly  used  they  will  help  him  toward 
his  goal.  Otherwise  he  resembles  the  man  in  the  fable 
who  worked  every  day  on  a  stone  wall,  and  who  every 
night,  when  he  was  asleep,  got  up  and  pulled  down  what 
he  had  done  the  day  before.  We  see  people  with  sound 


312  PHYSIOLOGY   AND   HEALTH 

bodies  but  with  minds  dull  and  inactive  through  lack 
of  mental  exercise;  they  resemble  trees  that  look  well 
but  never  bear  fruit. 

Nervousness.  —  We  frequently  hear  it  said  that  a 
child  or  a  grown  person  is  very  nervous  or  is  having  a 
"  nervous  breakdown. "  The  pioneers  in  our  country 
never  seemed  to  have  such  troubles,  although  they 
probably  worked  harder  than  the  busiest  men  of  to-day, 
showing  that  nervous  troubles  are  not  due  to  hard  work. 
The  pioneers  did,  however,  work  under  less  strain; 
to-day  the  complicated  conditions  of  business  competition 
bring  much  anxiety  and  worry,  and  that  will  cause  more 
trouble  than  hard  work  ever  does.  Neglect  of  the  body 
is  to-day  a  more  common  cause  of  "  nervousness  "  than 
overwork  of  the  mind.  Nervous  excitement  may  occa- 
sionally arise  from  some  diseased  condition  of  the  body. 
The  remedy  is  to  discover  the  cause  and  help  the  body  to 
right  itself ;  when  that  is  done,  the  nervousness  will  dis- 
appear. 

The  most  prevalent  form  of  nervousness  is  not  due  to 
physical  conditions  or  to  business  strain,  for  it  finds  its 
victims  chiefly  among  women  and  children.  Physicians 
are  agreed  that  this  is  the  most  serious  form  of  the  dis- 
order because,  not  being  physical,  it  cannot  be  reached 
by  physical  remedies.  The  sovereign  remedy  is  in  the 
training  of  the  will.  Children  and  young  people  are 
subject  to  those  forms  of  nervous  excitement  that  come 
from  lack  of  self-restraint.  If  denied  something  that  they 
desire,  or  required  to  do  something  that  they  dislike,  they 
become  "  nervous  "  or  hysterical,  and  their  friends  may 
say  that  they  are  too  "  delicate  "  to  be  crossed  in  any- 


BETTER  GOVERNMENT  OF  THE  BODY     313 

thing.  A  physician  would  state  the  situation  in  another 
way ;  he  would  say,  "  That  child  is  still  more  animal, 
than  human ;  the  trouble  is  not  with  his  nerves  but  with 
his  will." 

Over  and  over  again  it  has  been  proved,  by  physicians 
and  by  parents,  that  most  nervousness  is  only  a  form  of 
selfishness;  the  nervous  system  is  thrown  into  disorder 
because  the  individual  is  determined  to  get  his  own  way, 
regardless  of  the  rights  and  wishes  of  others.  Even  a 
very  young  child  can  understand  this.  The  cure  is  as 
much  in  his  own  hands  as  in  the  hands  of  his  elders. 
Every  human  being  ought  to  be  master  of  his  own  will. 
This  mastery  is  most  easily  acquired  when  one  is  young ; 
but  if  not  gained  then,  the  earlier  we  get  at  the  task,  the 
sooner  we  shall  conquer  and  the  happier  we  shall  be. 
When  the  will  is  strengthened,  nervousness  usually  dis- 
appears. 

A  good  beginning  is  to  make  oneself  do,  every  single 
day,  some  useful  or  kind  act  that  one  does  not  wish  to 
do,  —  such  as  giving  up  a  favorite  chair  or  book,  smiling 
when  one  feels  like  frowning,  saying  a  kind  word  when 
one  wishes  to  be  disagreeable.  If  some  such  thing  is 
done  day  by  day  with  this  deliberate  intention,  one  is 
sure  to  gain  control  of  the  will.  This  does  not  imply 
that  a  child's  will  should  "  be  broken,"  in  the  general 
meaning  of  that  old  phrase ;  just  the  opposite.  The 
difficulty  is  not  that  he  has  too  much  will,  but  that  it  is 
so  stiff  and  unyielding  that  he  himself  cannot  use  it.  He 
gains  will  power  as  he  learns  to  use  rightly  what  he  al- 
ready has,  for  the  will  grows  with  proper  use  just  as  much 
as  muscles  do. 


314  PHYSIOLOGY   AND    HEALTH 

QUESTIONS 

1.  What  part  of  the  brain  do  we  use  when  we  listen?     When  we 
look  at  a  picture?     When  we  think? 

2.  Relate  some  instances  in  your  experience  which  show  that 
animals  have  memory.     Have  you  ever  heard  of  instances  where  ani- 
mals seem  to  reason  ?     Do  you  believe  it  was  a  real  reasoning  ? 

3.  How  do  we  " exercise"  our  brains?     Can  our  brains  as  well  as 
our  muscles  be  made  strong  by  exercise  ?     What  would  happen  to  the 
brightest  mind  in  the  world  if  it  were  not  exercised  ? 

4.  Could  you  play  a  good  game  of  baseball  or  basket  ball  im- 
mediately after  a  hard  examination?     Could  you  do  as  well  in  an 
examination  immediately  after  a  hard  game?    Explain  your  answer. 

5.  When  do  you  find  it  easier  to  study  —  in  the  morning  or  in  the 
evening  ?     Why  ? 

6.  What  is  the  object  of  having  "recesses"  at  school?    Would  it 
not  be  better  to  do  all  your  work  at  once  so  as  to  have  uninterrupted 
time  for  play  afterward?    What  is  the  best  way  to  use  your  time  at 
recess?    Why  does  every  one  need  some  sort  of  recreation? 

7.  Name  some  subjects  on  which  you  find  it  easy  to  concentrate 
attention;   some  on  which  you  find  it  difficult.     If  your  mind  is  apt 
to  "wander,"  what  do  you  think  is  the  best  way  to  set  about  curing 
this  habit? 

8.  Why  is  it  important  that  a  schoolroom  be  quiet? 

9.  What  is  the  only  remedy  for  a  thoroughly  tired  brain  or  set  of 
muscles  ? 

10.  What  is  the  most  sensible  way  of  preparing  for  an  examination? 

1 1 .  How  much  sleep  does  one  ordinarily  require  ?     Do  you  see  any 
harm  in  attending  an  exciting  moving  picture  play  shortly  before  going 
to  bed? 

12.  Which  is  the  most  efficient  and  successful  person  —  one  who 
has  little  or  no  will  power,  one  who  has  a  strong  will  which  has  never 
been  controlled,  or  one  who  is  both  strong  willed  and  self-controlled? 

13.  Mention  some  ways  of  strengthening  the  will  power. 


CHAPTER  IV 
INTERFERENCE    WITH    THE    CONTROL    OF    THE    BODY 

Stimulants  and  Narcotics.  —  There  are  certain  sub- 
stances that  interfere  most  seriously  with  the  health 
and  vigor  of  various  parts  of  the  body;  they  are  some- 
times called  stimulants  and  sometimes  narcotics.  Let 
us  see  in  which  class  they  really  belong. 

Stimulants  increase  the  activity  of  the  body  or  of 
some  part  of  it.  For  example,  hot  water  stimulates 
heart  action ;  the  chewing  of  rubber  stimulates  the  se- 
cretion of  saliva;  strychnine,  when  used  in  minute 
quantities,  stimulates  the  heartbeat,  though  it  is  only 
a  temporary  stimulant,  in  the  end  reducing  the  activity 
of  the  heart. 

Narcotics  have  just  the  opposite  effect ;  they  soothe  and 
dull  the  action  of  the  body  and  have  a  tendency  to  put 
people  to  sleep.  By  decreasing  the  activities  of  the  brain, 
they  first  make  a  person  dull  and  stupid  ;  if  taken  in  large 
quantities,  they  make  him  totally  unconscious.  Although 
the  effects  of  narcotics  and  stimulants  are  so  different, 
they  are  often  confused,  particularly  in  the  case  of  cer- 
tain drugs  which  produce  both  effects.  When  used  in 
small  quantities,  such  drugs  have  the  effect  of  stimulants  ; 
but  when  used  in  large  quantities,  they  have  a  marked 
narcotic  effect.  Before  the  days  of  careful  laboratory 
tests  some  drugs  were  classed  as  stimulants  (because 

315 


316  PHYSIOLOGY   AND   HEALTH 

people  felt  stimulated  after  taking  them)  which  are  now 
clearly  demonstrated  to  be  narcotics.  The  person  who 
takes  them  is  simply  deceived ;  he  thinks  they  help  him 
to  work  better,  but  the  tests  show  that  he  is  actually  doing 
less. 

Opium 

Opium  quickly  dulls  the  senses ;  if  taken  in  sufficient 
quantity,  it  makes  a  person  totally  unconscious.  It  is 
one  of  the  most  dangerous  of  the  narcotics  because  it  has 
a  tendency  to  produce  a  terrible  craving  for  opium.  A 
person  may  begin  by  taking  a  small  amount,  often  merely 
to  relieve  serious  headache  or  neuralgia.  The  drug  not 
only  soothes  the  pain,  but  produces  a  restful  feeling  which 
he  enjoys.  Then,  especially  if  it  was  prescribed  by  his 
doctor,  he  may  acquire  the  habit  of  using  the  same  remedy 
whenever  he  has  a  real  or  an  imagined  pain,  for  the  sake 
of  the  pleasurable  effects.  Soon,  because  the  small 
doses  with  which  he  began  do  not  produce  the  desired 
effect,  he  takes  a  larger  amount ;  and  before  he  suspects 
the  fact  he  has  become  a  "  drug  fiend,"  the  slave  of 
opium,  no  longer  using  it  as  a  medicine  but  because  he  is 
miserable  without  it.  Opium  weakens  the  will,  destroys 
the  ability  to  think  clearly,  and  undermines  the  health, 
until  even  the  drug  itself  ceases  to  give  relief  or  satisfaction. 

Physicians  are  becoming  less  and  less  willing  to  pre- 
scribe opium  in  any  form,  because  so  many  people  con- 
tinue its  use.  To  use  it,  except  under  the  advice  of  a 
physician,  is  exceedingly  dangerous.  Paregoric,  lauda- 
num, morphine,  and  soothing  sirups  are  forms  of  opium 
and  should  all  be  avoided. 


INTERFERENCE  WITH   CONTROL  OF  THE  BODY     317 

Tobacco 

Tobacco,  a  mild  narcotic,  and  one  that  is  widely  used, 
is  by  no  means  to  be  classed  with  opium  and  other  dan- 
gerous narcotics  just  enumerated.  It  contains  neverthe- 
less a  poison  called  nicotine  which  is  dangerous  when 
taken  in  considerable  quantity.  Its  effect,  whether  in 
small  or  in  large  quantities,  is  much  more  marked  in 
young  people  than  in  adults.  For  young  people  tobacco 
is  always  found  to  be  harmful.  Adults  may  use  it 
moderately  without  showing  ill  effects  from  it,  but  when 
freely  used,  it  is  undeniably  injurious.  Following  are 
some  of  the  reasons  why  one  should  refrain  from  the  use 
of  tobacco : 

1.  The  use  of  tobacco  tends  to  check  the  growth  and  devel- 
opment of  the  body.     Careful  records  made  of  college  stu- 
dents show  that  those  who  are  addicted  to  the  use  of  tobacco 
are,  on  the  average,  less  developed,  both  as  to  muscles  and 
chest  capacity,  than  those  who  let  it  alone.  What  boy  wants 
to  handicap  his  physical  development  at  the  very  start  ? 

2.  The  use  of  tobacco  temporarily  reduces  one's  mus- 
cular power,  and  may  do  so  permanently. 

3.  The  use  of  tobacco  often  causes  heart  trouble.      A 
person  with  a  "  cigarette  heart  "  cannot  take  out  a  life  in- 
surance policy. 

4.  The  use  of  tobacco  is  likely  to  lead  boys  into  in- 
jurious company,  inviting  them  to  idleness  and  to  other 
bad  habits. 

5.  Tobacco  makes  boys  dull  at  their  studies.     The 
boys  in  your  school  who  use  cigarettes  will  almost  surely 
be  among  the  dull  scholars. 


318  PHYSIOLOGY   AND   HEALTH 

6.  Statistics  are  all  against  the  use  of  tobacco  by  young 
people ;  it  has  been  proved  in  many  different  ways  that 
the  boy  who  does  not  smoke  has  an  advantage  over  the 
one  who  smokes.  Of  that  there  can  be  no  doubt  at  all 
except  in  the  minds  of  those  who  do  not  know  the  facts. 
Some  of  these  facts,  proved  by  experiment  and  observa- 
tion, are  interesting. 

Only  ten  per  cent  of  the  cigarette  smokers  among  pupils 
in  city  schools  are  able  to  keep  up  with  their  grade. 

Only  one-half  as  many  smokers  as  non-smokers  are 
successful  in  tryouts  for  college  athletic  teams. 

Seventy-seven  per  cent  of  those  who  were  dropped  from 
a  certain  college  for  inability  to  keep  up  with  their  classes 
were  smokers. 

For  fifty  years  not  a  single  student  who  used  tobacco 
stood  at  the  head  of  his  class  in  Harvard  University. 

Cigarettes  undoubtedly  cause  more  injury  than  all 
other  forms  of  tobacco.  There  are  two  reasons  for  this. 
(1)  They  are  so  cheap  and  so  small  that  one  is  apt  to  smoke 
too  many  of  them.  (2)  The  smoke  from  them  is  almost 
always  "  inhaled  "  into  the  lungs  instead  of  being  taken 
into  the  mouth  only  (as  is  the  custom  generally  with  cigar 
smokers) ;  smoke  in  the  lungs  is  far  more  disastrous  than 
in  the  mouth,  since  the  lungs  are  especially  adapted  for 
absorbing  gases. 

Cigarettes  have  sent  many  people  to  insane  asylums, 
and  have  made  stunted  and  nervous  men  of  many  boys 
who  would  otherwise  have  been  well  grown,  strong,  and 
vigorous.  The  cigarette  habit  is  a  hopeless  handicap 
in  a  boy's  search  for  success  either  in  scholarship,  on  the 
athletic  field,  or  in  his  after  business  life.  The  boy  who 


INTERFERENCE  WITH   CONTROL   OF  THE  BODY      319 

does  not  acquire  this  habit  is  practically  sure  to  outdistance 
the  cigarette  smoker.  Cigarettes  lead  more  boys  to  the 
criminal  court  than  all  other  causes  together.  Out  of 
300  boys  that  came  before  one  such  court  295  were 
cigarette  smokers.  At  the  present  time  many  American 
boys  fall  victims  each  year  to  the  devastating  cigarette 
habit. 

Alcohol 

A  Narcotic.  —  Alcohol  is  another  drug  that  does 
great  injury.  In  the  form  of  beer,  wine,  or  the  stronger 
liquors  it  is  not  infrequently,  though  wrongly,  called  a 
stimulant.  Alcohol  is  undoubtedly  a  narcotic,  and  acts 
as  a  brain  poison.  Its  first  action  is  to  dull  the  powers  of 
self-restraint  in  the  brain,  thus  causing  a  person  to  say 
and  do  things  that  give  a  false  impression  of  strength. 
As  its  action  increases,  the  dulling  effect  becomes  more 
manifest ;  the  person  becomes  more  and  more  stupid, 
less  and  less  able  to  control  his  muscles,  and  finally 
when  he  becomes  completely  under  its  influence  he  is 
utterly  unable  to  think  or  to  work.  It  used  to  be  thought 
that  alcohol  increased  one's  power  to  do  hard  work,  but 
the  careful  investigations  of  recent  years  have  proved 
that  this  is  a  mistaken  notion ;  all  who  have  to  work 
hard  should  avoid  its  use. 

A  Foe  to  Success.  —  There  is  no  one  thing  that  pre- 
vents so  many  men  from  making  a  success  in  life  as  does 
the  use  of  alcohol.  If  some  new  disease  were  to  appear 
that  destroyed  hundreds  of  thousands  of  lives  every  year 
and  left  its  victims  so  demoralized  that  they  filled  the 
records  of  police  courts  and  insane  asylums  and  charity 


320  PHYSIOLOGY   AND   HEALTH 

organizations,  how  alarmed  we  should  be,  and  how  loudly 
we  should  call  upon  physicians  and  scientists  to  dis- 
cover some  way  to  stop  the  ravages  of  this  new  disease, 
and  to  prevent  its  spread.  So,  when  our  government 
experts  tell  us  that  every  eight  minutes  one  person  dies 
in  our  country  from  the  use  of  alcohol,  how  can  we  over- 
look the  enormity  of  the  danger? 

The  evidence  is  all  against  the  use  of  alcohol.  There 
is  no  denying  that  the  boy  who  begins  to  use  alcoholic 
drinks  becomes  dull  at  his  studies,  careless  in  his  habits, 
loses  his  ambitions,  associates  with  bad  companions,  and 
in  general  becomes  one  from  whom  not  much  that  is 
good  can  be  expected.  Any  young  person,  boy  or  girl, 
who  starts  to  make  a  place  in  the  world  needs  to  start 
with  all  possible  advantages;  the  most  valuable  advan- 
tages are  good  habits.  The  worst  possible  handicap  to 
a  boy's  success  in  life  is  to  have  it  said  of  him  that 
"  he  drinks." 

Moderate  Drinking.  —  Alcoholic  drinks,  even  when 
used  in  small  quantities,  produce  decided  effects  upon 
the  body,  but  those  effects  are  not  always  apparent. 
Little  by  little  the  injury  is  done.  Some  people  use  wines 
or  beers  in  small  amounts  for  years,  all  the  time  deny- 
ing that  they  are  injured  by  them.  They  are  doubtless 
honest  in  their  belief,  but  they  are  mistaken ;  for  it  has 
been  demonstrated  beyond  all  doubt  that  the  habitual 
use  of  alcoholic  drinks,  even  in  small  quantities,  has  dis- 
tinctly injurious  physical  effects.  Experimenters  have 
been  surprised  to  find  that  they  could  measure  the  de- 
crease in  muscular  power  that  resulted  from  taking  only 
two  drinks. 


INTERFERENCE  WITH   CONTROL  OF  THE  BODY     321 

The  strongest  temptation  comes  to  the  boy  before  he 
understands  what  the  results  of  drinking  are  likely  to  be. 
Of  drunkards,  over  one-half  acquire  the  habit  before  they 
are  twenty  years  of  age.  A  large  majority  of  them  begin 
to  drink  because  they  desire  to  be  sociable ;  they  commonly 
begin  with  beer,  which  friends  tell  them  is  harmless,  and 
so  they  consent  to  "  join  in  a  social  glass.'7  This  is  the 
beginning  of  the  road,  long  or  short,  that  leads  its  un- 
suspecting victim  to  drunkenness. 

Some  Recorded  Tests.  —  The  effect  of  alcohol  on  muscle 
power  was  shown  in  a  German  walking  match.  Of  the 
men  who  started  in  the  match  59  were  users  of  alcohol 
and  24  were  abstainers ;  60  per  cent  of  the  prizes  were 
captured  by  the  24  who  did  not  use  alcohol. 

Its  effect  on  endurance  is  illustrated  by  a  shooting  test 
in  the  Swedish  army.  On  some  days  the  soldiers  were 
allowed  to  have  a  little  alcohol  and  on  other  days  none. 
On  the  alcohol  days  they  could  fire  only  278  shots  before 
they  became  exhausted,  while  on  the  non-alcohol  days 
they  could  fire  360  shots.  Upon  their  quickness  and 
accuracy  alcohol  had  an  equally  unfortunate  effect ; 
for  on  the  alcohol  days  they  made  only  3  bull's  eye  shots 
out  of  a  possible  30,  while  on  the  non-alcohol  days  they 
made  24  out  of  a  possible  30.  In. the  great  European  war 
the  English  army  found  that  alcohol  destroys  accuracy 
in  shooting  and,  indeed,  in  everything  else.  In  iron  works, 
where  the  employment  is  dangerous,  the  deaths  from 
accidents  are  a  third  fewer  among  those  who  do  not  use 
alcohol  at  all. 

Its  effect  on  the  mind  is  shown  by  the  fact  that  at 
least  one  out  of  every  four  persons  sent  to  an  insane  asylum 


322  PHYSIOLOGY   AND   HEALTH 

became  deranged  through  the  use  of  alcohol.  Alcohol 
acts  primarily  upon  the  brain,  though  its  effect  is  un- 
fortunately not  always  apparent.  Even  a  small  amount 
of  alcohol  takes  away  one's  power  to  concentrate  his 
mind ;  the  result  is  that  he  cannot  work  as  fast  and  that 
he  makes  more  mistakes. 

It  lowers  the  power  of  resistance,  the  doctors  tell  us,  so 
that  even  the  "  moderate  "  drinker  has  less  chance  than 
a  non-drinker  to  recover  from  any  serious  disease.  The 
statistics  of  the  insurance  companies  show  that  moderate 
drinking  shortens  the  average  life  from  ten  to  thirteen 
years.  This  lowered  resistance  is  seen  not  only  in  the 
drinker  himself  but  in  his  children. 

Some  Recorded  Results.  —  When  the  great  European 
war  caused  the  nations  to  consider  in  real  earnest  the 
ways  in  which  the  prosperity  and  vitality  of  their  people 
were  being  lowered,  when  they  were  desperately  anxious 
to  strengthen  their  weak  spots,  they  decided  that  they 
could  not  risk  the  continuance  of  alcohol  drinking.  In 
one  form  or  another  citizens  called  on  each  other  to 
show  love  of  country  by  giving  up  the  use  of  intoxicat- 
ing drinks  during  the  continuance  of  the  war,  and  the 
sentiment  was  so  strong  in  favor  of  this  that  country 
after  country  made  .regulations  either  prohibiting,  or 
greatly  restricting,  the  use  of  alcoholic  beverages.  What 
happened?  In  Russia,  the  deposits  in  the  savings  banks 
for  the  poorer  classes  increased  from  $350,000  in  Decem- 
ber, 1913  to  $15,000,000  in  December,  1914.  One  of  the 
insurance  companies  in  Russia  estimated  that  crime  di- 
minished 62  per  cent  during  the  first  year  of  prohibition. 

In  England,  the  prohibition  of  treating  in  the  city  of 


INTERFERENCE   WITH   CONTROL  OF  THE  BODY      323 

London  caused  a  reduction  in  the  number  of  cases  of 
drunkenness  of  between  30  and  40  per  cent.  Total  absti- 
nence was  forcefully  urged  in  England  during  the  second 
year  of  the  war  on  the  ground  that  the  $800,000,000 
annually  spent  for  drink  was  only  a  small  part  of  what  it 
actually  cost  the  country.  It  is  stated  that  of  the  668,000 
working  hours  lost  every  week  in  the  ship  building  trade 
alone,  80  per  cent  of  this  loss  was  due  to  drink. 

QUESTIONS 

1.  What  is  the  general  effect  of  stimulants  on  the  body?    Of 
narcotics?     Is  alcohol  a  stimulant  or  a  narcotic? 

2.  What  effect  has  opium  on  the  body  ?     On  the  mind  and  char- 
acter?    How  is  the  habit  frequently  acquired?    Explain  why  it  is 
difficult  to  throw  off  the  habit. 

3.  What  poison  is  found  in  tobacco?    What  harmful  effects  has 
tobacco  on  the  system  of  a  growing  boy? 

4.  What  is  the  most  injurious  form  of  tobacco?    Why? 

5.  If  a  boy  were  to  begin  smoking  at  the  age  of  twelve,  spending 
ten  cents  each  day  for  cigarettes,  how  much  money  would  he  have 
spent  in  this  way  by  the  time  he  was  twenty-one? 

6.  Are  there  any  laws  in  your  state  regarding  the  purchase  or  use 
of  tobacco  by  boys? 

7.  How  does  even  a  moderate  drinker  lessen  his  chances  of  re- 
covery, in  case  he  is  attacked  by  a  serious  illness? 

8.  What  was  done  by  the  nations  engaged  in  the  European  War  of 
1914  towards  prohibiting  the  use  of  alcohol?    What  were  the  results? 

9.  If  the  use  of  liquor  were  prohibited  in  this  country  for  the  next 
fifty  years,  what  effect  do  you  think  it  would  have  on  our  jails,  poor- 
houses,  insane  asylums,  institutions  for  the  feeble-minded? 

10.  Why  do  railroad  companies  refuse  to  employ  men  who  drink? 


CHAPTER  V 

THE   PART   PLAYED   BY   THE   SPECIAL   SENSES 
Sight 

THE  operator  shut  up  at  the  "  central  "  station  of  a 
telephone  system  knows  much  that  is  going  on  all  over 
the  city  by  the  messages  that  keep  coming  in.  "  Cen- 
tral/' too,  can  send  messages  all  over  the  city.  The 
"  central  station  "  of  the  body  is  in  the  brain,  shut  up 
in  its  bony  box,  the  skull.  From  this  station,  as  we  have 
seen,  nerves  extend  to  every  part  of  the  body ;  there  are 
the  motor  nerves  that  carry  messages  or  orders  to  the 
different  parts  .of  the  body ;  and  there  are  the  sensory 
nerves  which  carry  messages  that  cause,  when  they  reach 
the  brain,  what  are  called  sensations,  giving  us  news  of 
the  outer  world  as  well  as  of  the  different  parts  of  the 
body. 

The  sensory  nerves  end  in  organs  called  sense  organs. 
Many  of  these  sense  organs  are  very  simple,  having  only 
simple  functions  to  perform,  like  that  of  receiving  touch, 
heat,  and  pain  stimuli.  Of  these  some  are  excited  by 
pressure  on  the  skin,  which  immediately  sends  an  impulse 
to  the  neurons  in  the  brain,  causing  a  sensation  which  we 
call  touch.  A  burning  match  or  a  piece  of  ice  may  excite 
other  sense  organs  in  the  skin,  giving  us  sensations  of 

324 


THE  PART  PLAYED  BY   THE  SPECIAL  SENSES      325 

heat  or  cold  when  these  impulses  reach  the  brain  and 
are  interpreted. 

There  are  other  sensory  nerves,  however,  which  end  in 
much  more  elaborate  sense  organs,  such  as  the  eye  and 
ear.  The  eye  is  an  organ  that  is  excited  by  light  waves, 
the  ear  by  sound  waves ;  the  messages  from  these  organs 
give  us  sensations  which  we  call  sight  and  sound.  Other 
organs  —  those  in  the  mouth  and  nose  —  give  us  sen- 
sations of  taste  and  smell. 

Our  various  sensations  may  be  arranged  in  two  groups  : 
(1)  General  sensations,  like  pain,  'hunger,  and  thirst, 
which  tell  us  of  the  condition  of  parts  of  the  body.  (2) 
Special  sensations,  sight,  hearing,  taste,  smell,  and  touch, 
—  our  "five  senses,"  and  some  others — which  are  caused 
by  impressions  from  things  outside  the  body.  These  give 
us  all  our  knowledge  of  the  outer  world. 

The  Eye 

When  we  speak  of  the  eye,  we  seldom  think  of  it  as  a 
sphere.  The  front  part  of  the  eyeball  is  the  only  part 
that  is  seen  as  we  look  into  one's  eyes  ;  the  rest  of  it,  which 
is  almost  a  perfect  sphere  about  one  inch  in  diameter, 
being  covered  by  the  lids,  or  hidden  in  the  deep  sockets 
in  the  front  of  the  skull.  We  talk  of  large  eyes  and  small 
eyes,  yet  the  dimensions  of  the  eye  really  do  not  vary 
much.  There  is,  however,  a  great  difference  in  the  ex- 
tent to  which  the  eyelids  cover  the  eyeball.  The  eye 
looks  large  or  small  according  as  the  eyelids  are  opened 
wide. or  are  partly  closed.  Figure  88  shows  the  eye  as  it 
really  is,  a  ball  set  into  a  deep  socket  in  the  front  of  the 


326 


PHYSIOLOGY   AND   HEALTH 


skull,  with  only  its  front  surface  exposed.  This  bony 
socket  is  of  great  service  in  guarding  the  eye  from  injury 
through  blows  and  falls. 

The  Protectors  of  the  Eye.  —  The  front  of  the  eye  is 
protected  by  the  eyelids,  two  folds  of  skin  that  hang  over 


FIG.  88.  —  THE  EYEBALL. 

It  is  represented  natural  size,  and  in  position  in  the  eye  socket,  with  the 
chief  muscles  that  move  it. 

the  eye,  one  from  above  and  the  other  from  below.  A 
portion  of  the  front  of  the  eye  is  always  covered  by  these 
lids,  and  they  are  constantly  being  closed  and  opened. 
When  closed,  they  protect  the  eye  and  keep  its  delicate 
surface  clean  and  moist.  If  the  lids  did  not  constantly 
cleanse  the  surface,  if  the  tear  secretions  did  not  wash  the 
dust  away,  the  eye  would  become  inflamed.  So  the 
eyelids  keep  closing  every  few  seconds,  with  a  movement 
that  we  never  notice  in  our  own  eyes,  but  which  one  can 


THE  PART  PLAYED  BY  THE   SPECIAL  SENSES      327 


easily  observe  in  the  eyes  of  others.  By  their  long  lashes 
which  assist  in  keeping  out  the  dust,  and  by  their  exceed- 
ingly quick  motions,  the  lids  also  serve  to  guard  the  eye 
against  accident. 

How  the  Eye  Is  Kept  Clean.  —  Just  above  each  eye, 
on  the  side  next  the  temple,  is  a  small  tear  gland  or 
lachrymal  gland,  which  produces  a  watery  liquid  that 
flows  down  over  the  surface  of  the  eye  and  keeps  it  moist. 
On  the  inner  edge  of  the  eye,  near  the  nose,  there  is  a  tube, 
called  the  tear  duct, 
which  empties  into  the 
cavity  inside  the  nose. 
After  the  tears  have 
washed  the  surface  of 
the  eye,  they  pass 
through  the  tear  duct 
into  the  nose,  and 
then  to  the  throat, 
where  they  are  swal- 
lowed. (The  expres- 
sion "  she  swallowed 
her  tears "  has  good 
physiological  founda- 
tion.) Usually  the 
tear  gland  produces 
just  liquid  enough  to  wash  the  eyeball  and  that  amount 
passes  easily  down  the  tear  duct.  Sometimes  under  the 
influence  of  strong  emotion  tears  are  produced  faster  than 
the  duct  can  carry  them  off.  Then  one  "  cries/'  The 
tears  overflow  the  eyes  and  run  down  the  cheeks.  A 
similar  thing  happens  when  the  tear  duct  is  stopped  up. 


FIG.  89.  —  THE  EYE  FROM  IN  FRONT. 

The  figure  shows  the  location  of  the  lachrymal 

gland,  L.g.,  and  the  lachrymal  duct,  L.d. 


328 


PHYSIOLOGY   AND   HEALTH 


Then  one  becomes  conscious  of  the  amount  of  moisture 
that  is  being  constantly  drained  off  from  the  eye. 

What  Moves  the  Eyes  ?  —  The  eyes  make  an  incredible 
number  of  movements  every  hour.  Of  most  of  these  we 
are  entirely  unconscious ;  they  are  largely  voluntary 
movements,  but  are  made  under  the  direction  of  highly 
trained  groups  of  neurons  which  require  little  conscious 
attention  from  us.  The  motions  of  the  eye  are  controlled 
by  six  tiny  muscles  attached  to  each  eyeball.  One  is  on 
the  top,  one  on  the  bottom,  one  on  each  side,  and  two 
obliquely  placed,  as  is  shown  in  Figure  88.  By  the  con- 
traction of  the  different  muscles  the  eyeball  can  be  turned 
in  any  direction. 

The  Eye  as  a  Camera.  —  Nature  made  a  camera  long 
before  man  ever  learned  how  to  do  it.  A  photographic 
camera  has  three  essential  parts :  (1)  a  dark  chamber, 

the  box  of  the  camera, 
which  is  so  closed  as 
to  admit  light  only 
from  the  opening  in 
front ;  (2)  a  lens 
which  is  placed  across 
the  front  opening, 
and  which  makes  an 
image  of  the  object 
to  be  photographed ; 
(3)  a  sensitive  plate, 
located  at  the  back  of  the  camera,  upon  which  the  picture 
is  taken.  The  human  eye  has  its  dark  chamber  and  its 
lens  and  its  sensitive  surface  at  the  back;  Figure  91 
shows  the  comparison  between  the  eye  and  the  camera. 


Cornea 


FIG.  90.  —  SECTION  OF  THE  HUMAN  EYE. 


THE  PART  PLAYED  BY  THE   SPECIAL  SENSES     329 


The  eye's  dark  chamber  is  the  eyeball  which  admits 
light  only  from  the  front.  Its  lens  is  at  the  point  at  which 
light  is  admitted.  At  the  back  of  the  rounded,  dark  cham- 
ber is  a  sensitive  surface  called  the  retina.  Between  the 
front  of  the  eye  and  the 
retina  the  eyeball  is  filled 
with  transparent  liquids, 
through  which  the  light 
can  easily  pass. 

The  pupil  of  the  eye  is 
the  small  opening  in  the 
front  through  which  the 
light  passes.  You  see  it 
as  a  black  spot  in  the 
middle  of  the  eye.  If 
you  look  at  the  pupils 
of  another  person's  eyes 
when  he  is  in  a  bright  light,  you  will  find  that  they  are 
very  small,  and  that  they  are  much  larger  in  a  dim  light ; 
for  then  the  opening  is  enlarged  to  let  in  as  much  light 
as  possible.  The  pupils  of  a  cat's  eyes  open  wider  than 
ours  can,  which  is  one  reason  why  cats  see  in  the  dark 
better  than  we  can. 

The  transparent  lens  just  inside  the  pupil  is  so  shaped 
that  when  rays  of  light  strike  it,  their  direction  is  changed 
and  they  come  together  (focus)  at  the  back  part  of  the 
eye.  If  you  could  look  at  the  retina,  you  would  find 
upon  it  a  tiny  picture  or  image  of  the  object  at  which 
the  eye  is  looking  and  from  which  the  light  comes. 
This  image  is  similar  to  what  we  see  on  the  ground-glass 
screen  at  the  back  of  a  photographic  camera.  The  image 


FIG.  91.  —  Two  CAMERAS. 
A  diagram  showing  the  similarity  in  the 
structure  of  a  photographic  camera  and 
the  eye. 


330  PHYSIOLOGY   AND   HEALTH 

changes  as  rapidly  as  the  eye  is  turned  from  one  object  to 
another.  But  you  must  not  think  of  the  brain  as  looking 
at  the  picture  on  the  retina.  The  process  is  far  more 
complicated  than  that. 

The  retina  is  full  of  nerves  which,  stimulated  by  the 
light  waves  coming  from  the  object  looked  at,  send  im- 
pulses to  the  brain.  These  impulses  the  brain  receives 
and  interprets  as  the  picture.  We  could  not  see  if  the 
nerves  that  connect  the  eye  with  the  brain  were  severed, 
because  the  message  would  never  reach  the  brain.  Nor 
could  we  see,  with  perfect  nerves,  if  the  eye  were  so  injured 
that  no  image  could  be  formed  on  the  retina. 

The  photographer  has  to  change  the  focus  of  his  camera 
when  he  turns  it  from  a  distant  object  to  take  a  picture 
of  an  object  near  by.  So  the  lens  of  the  eye  has  to  be 
changed  when  we  look  from  a  distant  object  to  one  close 
at  hand.  If  we  are  observing  a  distant  hill,  for  example, 
and  wish  to  read  a  description  of  it  from  a  book  in  our 
hands,  the  shape  of  the  lens  must  be  changed  before  the 
book  can  be  sharply  pictured  on  the  retina ;  when  this  is 
done,  the  image  of  the  hill  necessarily  becomes  somewhat 
blurred  while  the  image  of  the  book  is  sharp  and  clear. 
These  changes  in  the  lens  are  made  very  rapidly  by  a 
delicate  little  muscle  which  works  with  great  accuracy. 

Figure  90  shows  a  cross  section  of  the  eye.  In  that 
figure,  the  part  labeled  "  vitreous  body  "  corresponds  to 
the  dark  chamber.  The  transparent  layer  in  the  very 
front  of  the  eye  is  named  the  cornea,  and  the  membrane 
or  veil  which  contains  all  of  the  color  is  called  the  iris. 
It  is  the  iris  that  makes  the  eyes  blue  or  brown.  It  is  a 
change  in  the  shape  of  the  iris  that  opens  and  closes  the 


THE  PART  PLAYED   BY   THE   SPECIAL  SENSES      331 

<~~r 

pupil,  which  is  the  opening  in  the  middle  of  this  iris.  The 
sensitive  part  of  the  eye  is  at  the  very  back  of  the  eyeball, 
and  is  called  the  retina. 

Nearsightedness.  —  If  the  eyeball  and  the  lens  are  of 
exactly  the  right  shape,  we  can  focus  our  eyes  so  as  to  see 
near-by  or  distant  objects  at  will.  If  the  eyeball  is  a  little 
too  long,  or  if  the  lens  is  a  little  too  bulging,  we  can  focus 
near-by  objects  on  the  retina  clearly  and  sharply,  but  dis- 
tant objects  will  be  somewhat  blurred.  We  say  that  a 
person  who  has  this  difficulty  is  nearsighted;  in  order 
to  see  distant  objects  clearly,  he  must  wear  glasses  so 
prepared  as  just  to  correct  the  defect  in  his  eyes. 

Some  people  are  born  nearsighted,  but  this  form  of  de- 
fective vision  is  more  often  caused  by  improper  habits  of 
study.  Children  frequently  lean  over  a  desk  or  a  table 
when  they  read,  thus  bringing  the  book  too  close  to  the 
eyes.  This  habit  causes  a  strain  upon  the  eyes,  which  in 
time  causes  such  changes  that  the  eyes,  which  at  first  had 
normal  vision,  can  after  a  time  see  clearly  only  objects  that 
are  close  by.  Those  who  live  out  of  doors,  and  who  do 
little  or  no  reading,  seldom  have  this  trouble;  they  are 
constantly  looking  at  objects  more  or  less  distant  from 
them.  We  should  not  be  likely  to  become  nearsighted  if 
we  always  held  our  books  fourteen  inches  or  more  from 
our  eyes.  How  close  do  you  hold  your  book  when  reading 
or  writing?  If  you  cannot  see  clearly  without  holding 
your  book  within  six  or  eight  inches,  you  are  either  near- 
sighted, or  are  likely  to  become  so.  Your  eyes  should  be 
examined  by  an  oculist. 

Farsightedness.  —  Other  defects  in  the  shape  of  the 
eyeball  and  the  lens  produce  farsightedness,  and  still 


332  PHYSIOLOGY   AND   HEALTH 

other  defects  cause  a  trouble  called  astigmatism,  both  of 
which  interfere  with  clear  vision. 

Color  Blindness.  —  There  are  some  people  who,  be- 
cause they  cannot  distinguish  between  the  most  common 
colors,  are  said  to  be  color  blind  ;  the  colors  most  frequently 
confused  by  them  are  reds  and  greens.  Their  vision 
may  not  be  impaired  in  any  other  way,  and  frequently 
they  do  not  know  of  the  defect. 

The  Care  of  the  Eyes.  —  1.  Use  the  eyes,  for  it  certainly 
does  them  no  harm  to  be  exercised ;  they  were  made  for 
use.  Constant  use  on  close  work  such  as  reading  or  em- 
broidery tires  them,  and  too  long  a  strain  may  injure 
them.  The  remedy,  however,  is  a  simple  one.  Close  the 
eyes  occasionally  for  a  moment,  or  look  at  some  distant 
object.  This  will  give  rest  to  the  muscles  that  have  been 
keeping  the  eyes  focused  too  steadily  in  one  position. 

2.  Control  the  light.     Never  abuse  the  eyes  by  reading 
in  a  dim  light,  or  worse  still,  in  a  flickering  light.     The 
flickering  light  of  the  steadiest  "  movies  "  is  certainly  bad 
for  the  eyes,  and  while  a  little  of  it  may  not  do  serious  harm, 
children  who  frequent  the  "  movies  "  are  surely  laying  the 
foundation  for  eye  troubles.       When  we  read,  the  light 
should  fall  upon  the  book  and  not  into  our  eyes.     Pref- 
erably the  light  should  come  from  above,  and  from  over 
the  left  shoulder;  but  a  very  bright  light,  like  the  sun's 
direct  rays,  should  not  be  allowed  to  fall  upon  the  book. 
Daylight  is  better  than  artificial  light  and  white  light 
better  than  light  of  any  other  color. 

3.  Hold  the  head  erect  when  reading.     To  read  in  a 
reclining  position  is  taxing  to  the  eyes  and  does  them 
injury.     If  the  brain  is  really  fatigued,  it  is  a  bad  plan  to 


THE  PART  PLAYED  BY  THE  SPECIAL  SENSES      333 

read  while  lying  down.  This  means  setting  the  tired 
brain  a  new  task,  that  of  controlling  the  work  of  the 
eyes,  and  under  conditions  bad  for  the  eyes  themselves. 
It  is  better  to  give  the  brain  a  shorter  but  more  complete 
rest  by  lying  down  with  the  eyes  closed  for  a  few  moments. 

4.  Watch  the  eyesight.     If  there  is  difficulty  in  seeing, 
if  the  eyes  become  inflamed,  or  if  there  is  a  tendency  to 
headache,   the  eyes  should  be  examined  by  an  oculist. 
Headaches  that  are  due  to  eye  trouble  are  often  cured 
by  the  use  of  glasses  prescribed  by  a  competent  oculist. 

5.  Remove  dust  particles  that  get  into  the  eyes.     Usually 
bits  of  dust  are  washed  away  by  the  tears  and  carried 
into  the  tear  duct.     If  not  dislodged  in  this  way,  they 
may  frequently  be  dislodged  by  lifting  the  upper  eyelid 
with  the  fingers  and  drawing  it  down  over  the  lower  eye- 
lid.    If  not,  some  competent  person  can  usually  discover 
where  the  particle  of  dust  is,  and  can  remove  it  with  the 
end  of  a  soft  handkerchief  rolled  up  to  a  point.     If  this 
attempt  fails,  a  physician  should  be  asked  to  attend  to  it, 
as  the  particle  should  not  be  allowed  to  remain.     In  such 
cases  the  natural  flow  of  tears  is  increased,  to  help  in  re- 
moving the  trouble,  the  eye  becomes  inflamed,  and  there 
is  temptation  to  try  to  rub  the  particle  out;    that  will 
only  increase  the  difficulty.     Never  rub   the  eyes.     Any 
one  who  has  eye  trouble  should  consult  a  physician  or  an 
oculist  at  once.     Failure  to  do  this  often  means  lifelong 
trouble.     The  eyes  are  so  infinitely  important  to  us  that 
they  should  be  guarded  with  every  care.    Never  have  them 
treated  by  incompetent  people. 

Diseases  of  the  Eyes.  —  Pink  eye  and  trachoma  (or 
granulations)  are  two  rather  common  diseases  of  the  eye. 


334  PHYSIOLOGY   AND    HEALTH 

Both  of  these  diseases  are  contagious  and  are  often  com- 
municated by  the  use  of  a  public  towel. 

QUESTIONS 

1.  Distinguish  between  general  sensations  and  special  sensations. 

2.  Can  you  see  why  the  eye  needs  to  be  a  very  much  more  complex 
organ  than  are  the  sense  organs  of  touch  ? 

3.  What  is  the  shape  of  the  eyeball?    How  much  of  it  can  one  see? 

4.  Why  do  we  have   eyelids?     Eyelashes?    Eyebrows?     What 
does  the  flow  of  tears  usually  accomplish? 

5.  Why  do  you  think  one's  eyes  are  often  inflamed  and  watery 
when  one  has  a  cold? 

6.  In  how  many  directions  can  you  turn  your  eyes?     How  are 
these  movements  made  possible? 

7.  What  part  of  the  eye  corresponds  to  the  "dark  chamber"  of  a 
camera?    What  corresponds  to  the  lens  of  the  camera?     What  part 
corresponds  to  the  sensitive  plate  ? 

8.  Do  the  lenses  of  the  eye  have  to  be  focused?    Are  we  conscious 
of  this? 

9.  Watch  your  cat's  eyes.     How  do  they  look  on  a  bright  day? 
On  a  cloudy  day?    At  night?     Account  for  the  changes. 

10.  Do  you  think  there  are  pictures  in  the  brain  of  all  the  objects 
you  have  ever  seen  ?    Why  ? 

11.  Why  is  it  advisable  for  a  person  who  is  reading  to  look  away 
from  his  book  occasionally? 

12.  Do  you  know  any  one  who  is  nearsighted?    Any  one  who  is 
f arsighted  ?     Do  they  wear  the  same  kind  of  glasses  ? 

13.  What  might  happen  if  the  engineer  of  a  train  were  color  blind? 

14.  Write  a  set  of  rules  that  one  should  follow  if  he  would  avoid 
eye  troubles. 

15.  About  how  far  from  the  eyes  should  the  book  be  held? 


CHAPTER  VI 

THE  PART  PLAYED  BY  THE  SPECIAL  SENSES  (Continued) 
Hearing  and  Other  Senses 

The  Organ  of  Hearing.  —  We  never  see  the  real  organ 
of  hearing,  the  inner  ear,  for  it  is  embedded  in  bones 
inside  the  head.  The  hardest  bone  in  the  body,  called 
the.  stony  bone,  surrounds  this  inner  ear,  and  gives  it 
great  protection  from  injury. 

The  outer  parts  of  the  ear,  the  bits  of  cartilage  covered 
with  skin  which  are  commonly  called  the  ear,  probably  help 
to  collect  air  waves  and  to  intensify  sounds. 

Structure  of  the  Ear.  —  From  the  outer  ear  we  see  an 
opening  that  leads  to  a  slightly  bent  passage,  which  is 
kept  moist  by  the  sticky  secretion  that  we  know  in  its 
hardened  form  as  ear  wax.  The  passage  is  closed  at  the 
inner  end  by  a  tough,  elastic  membrane,  the  eardrum 
(tympanic  membrane),  which  is  stretched  across  it. 
Beyond  the  membrane  there  is  a  small  cavity,  often  called 
the  middle  ear,  on  the  lower  side  of  which  is  an  opening 
leading  into  the  Eustachian  tube.  This  tube,  extending 
into  the  throat,  is  opened  every  time  we  swallow;  in 
this  way  the  middle  ear  is  kept  filled  with  air,  and  the 
air  pressure  within  and  without  is  kept  the  same.  If 
the  air  pressure  outside  were  greater  than  the  pressure 
inside,  the  tympanic  membrane  would  be  pushed  in, 
while  it  would  be  pushed  out  if  the  pressure  within  were 

335 


336 


PHYSIOLOGY   AND   HEALTH 


greater.     In  either  case  the  hearing  would  be  affected. 
The  purpose  of  the  tube  is  to  equalize  the  air  pressure. 


FIG.  92. —  THE  HUMAN  EAR. 

Shown  in  section.  Co. ,  cochlea  (location  of  the  real  hearing 
organ)  ;  E.b.,  ear  bones;  Eu.,  Eustachian  tube;  Ty.m., 
tympanic  membrane. 

How  We  Hear.  —  Across  the  cavity  of  the  middle  ear 
are  stretched  the  three  small  bones  which  appear  in  Figure 
92.  The  outer  of  these  ear  bones  is  attached  to  the  ear- 
drum and  the  inner  bone  connects  with  the  inner  ear, 
which  contains  the  real  hearing  organ.  The  three  bones 
are  so  connected  that  when  waves  of  air  enter  the  ear,  the 
tympanic  membrane  is  set  to  vibrating.  This  vibration 
is  carried  to  the  bone  which  is  attached  to  the  tympanic 
membrane  and  thence  through  the  other  two  bones  to  the 
inner  ear,  where  it  reaches  many  nerves.  The  effect  of 
the  vibration  upon  these  nerves  is  to  start  nervous  impulses 


THE  PART  PLAYED  BY  THE  SPECIAL  SENSES     337 

which  travel  rapidly  to  the  brain,  and  there  produce  a 
sensation  which  we  call  hearing. 

What  Hearing  Tells  Us.  —  Our  ears  give  us  many  bits 
of  useful  information  concerning  the  world.  They  tell 
us  something  of  distance ;  for  if  we  know  what  causes  a 
certain  sound,  we  can  judge  how  far  away  it  is  by  its  loud- 
ness.  Comparative  loudness  is  our  only  clew  to  sound 
distances. 

We  cannot  be  at  all  accurate  in  determining  the  direc- 
tion from  which  sound  comes.  If  it  sounds  louder  in  one 
ear  than  in  the  other,  we  reason  that  the  sound  comes  from 
the  side  where  it  seems  loudest. 

By  practice  we  learn  to  discover  many  wonderful  and 
valuable  things  by  means  of  what  the  ears  tell  us. 

Care  of  the  Ears.  —  The  ears  require  chiefly  to  be  let 
alone ;  if  they  need  care,  it  is  usually  such  as  only  a  phy- 
sician should  give.  The  earwax  which  accumulates  in 
the  outer  passage  may  need  to  be  removed  because  it  is 
unsightly.  To  remove  it,  the  end  of  the  little  finger  or  a 
rolled  end  of  a  handkerchief  can  safely  be  used,  but  pointed 
objects,  like  pins  or  needles,  should  never  be  used,  except 
by  a  physician.  There  is  danger  of  injury  by  perforating 
the  membrane  of  the  eardrum.  Boxing  children's  ears  may 
injure  the  membranes.  Sometimes  very  loud  noises,  like 
explosions,  will  break  the  membrane  and  cause  deafness. 

Slight  pain  in  the  ears,  caused  by  a  slight  inflammation 
in  or  around  the  Eustachian  tube,  may  frequently  be 
relieved  by  the  application  of  hot  cloths  or  a  hot  water 
bag,  both  of  which  serve  to  call  some  of  the  excess  blood 
from  the  inflamed  part  to  the  surface. 

Serious  earache  in  children  is  usually  caused  by  sores 


338  PHYSIOLOGY   AND   HEALTH 

in  the  ear;  these  occasionally  make  little  holes  through 
the  membrane,  which  interfere  somewhat  with  hearing. 
A  physician  might  prevent  this,  if  consulted  in  time. 

A  cold  in  the  head  sometimes  causes  slight  tem- 
porary deafness.  The  inflammation  in  the  throat  partly 
closes  the  opening  from  it  into 'the  ears.  Throat  troubles 
are  apt  to  extend  to  the  ears  and  are  the  most  common 
causes  of  deafness.  A  physician  examines  the  throat 
first  when  he  is  looking  for  a  cause  of  deafness.  Some- 
times he  finds  that  the  person  has  catarrh,  and  sometimes 
that  little  growths,  called  adenoids  (see  page  133),  block 
up  the  passage  from  throat  to  ear.  When  the  catarrh 
is  cured,  or  the  adenoids  are  removed,  the  deafness  fre- 
quently disappears. 

Deafness  and  Dullness.  —  Frequently  a  pupil  is  ap- 
parently inattentive  and  dull  when  the  only  trouble  is 
that  he  never  hears,  as  clearly  as  others  do,  the  questions 
asked  or  the  explanations  given  by  the  teacher ;  so  he  is 
confused  or  indefinite  in  his  answers.  He  does  not  realize 
that  he  has  any  difficulty  in  hearing,  and  it  may  never 
occur  to  his  teacher  or  to  his  parents  that  his  habitual 
inattention  is  due  to  a  slight  deafness.  In  all  such  cases 
the  hearing  should  be  tested,  and  a  physician  should  be 
consulted  if  any  defect  is  discovered.  A  dull,  inattentive 
pupil  is  sometimes  converted  into  a  bright  one  by  a  visit 
to  a  competent  physician. 

Temporary  deafness  often  results  from  colds  that  affect 
the  throat,  but  such  deafness  should  disappear  in  two  or 
three  days.  If  it  continues,  a  physician  should  be  con- 
sulted promptly,  before  the  delicate  parts  of  the  hearing 
mechanism  have  become  involved  in  any  serious  trouble. 


THE   PART  PLAYED  BY  THE  SPECIAL  SENSES     339 

Taste 

How  We  Taste  Things.  --  There  are  certain  substances 
that  seem  tasteless  to  us  because  they  do  not  readily  dis- 
solve in  the  saliva  of  the  mouth,  and  so  do  not  produce 
taste.  Solid  bodies  do  not  give  us  the  sensation  of  taste 
until  they  are  more  or  less  dissolved  in  the  saliva.  This 
is  readily  demonstrated  with  a  solid  lump  of  sugar,  a 
substance  which  dissolves  very  quickly.  If  the  tongue  is 
rubbed  dry,  a  lump  of  sugar  placed  upon  it  gives  us  no  sweet 
taste  until  the  liquids  of  the  mouth  have  time  to  begin 
dissolving  the  sugar. 

The  organs  of  taste  are  located  in  the  upper  side  of  the 
tongue  and  in  the  roof  of  the  mouth.  The  sensation  of 
taste  is  strongest  when  a  substance  is  rolled  around  by 
the  tongue  at  the  back  of  the  mouth.  By  looking  at  the 
tongue  in  a  hand  mirror  we  see  that  it  is  covered  with 
numerous  little  bunches  or  papillae ;  they  differ  in  ap- 
pearance and  also  vary  in  use.  Some  of  those  at  the 
back  of  the  mouth  are  associated  with  the  sense  of  taste 
and  contain  what  are  called  taste  buds. 

The  tongue  is  made  up,  for  the  most  part,  of  muscles 
which  run  in  many  directions,  thus  enabling  us  to  move 
it  very  easily.  In  addition  to  the  muscles  the  tongue  has 
many  glands,  which  secrete  a  watery  substance  that  keeps 
it  moist.  There  are  also  many  blood  vessels  and  nerves, 
some  of  which  are  particularly  concerned  with  carrying 
to  the  brain  the  messages  that  enable  us  to  determine 
the  presence  of  sweet,  sour,  salt,  or  bitter  substances. 

If  the  tongue  is  not  of  a  pinkish  red  color,  it  is  usually 
a  sign  that  the  stomach  is  out  of  order.  A  physician 


340  PHYSIOLOGY   AND    HEALTH 

commonly  examines  the  tongue  to  detect  signs  of  trouble 
with  the  digestive  organs.  If  it  is  covered  with  a  whitish 
or  yellowish  coating,  or  if  it  is  bright  red,  he  knows  that 
something  is  wrong. 

Kinds  of  Taste.  —  Many  sensations  that  we  call  taste 
are  really  sensations  of  taste  and  smell  combined ;  and 
we  are  so  dependent  upon  this  combination  that  we  can- 
not readily  distinguish  between  familiar  substances  by 
the  sense  of  taste  alone.  If  a  person  closes  his  eyes 
tight  and  holds  his  nose,  so  that  he  cannot  catch  the  least 
odor,  it  will  be  found  that  he  cannot  readily  distinguish 
between  apple,  onion,  and  potato  if  they  are  given  to  him 
successively  and  in  small  pieces.  When  you  eat  your 
dinner,  notice  how  much  the  temperature  and  odor  of 
the  food  have  to  do  with  your  enjoyment  of  its  taste. 

All  tastes  may  be  classified  under  four  heads :  bitter, 
sweet,  acid  (sour),  and  salt.  The  different  tastes  are 
not  perceived  equally  well  in  all  parts  of  the  mouth ; 
for  instance,  we  taste  sweet  things  most  delicately  at 
the  tip  of  the  tongue,  and  bitter  things  at  the  back 
part  of  the  mouth.  This  suggests  that  when  we  have 
bitter  medicine  to  take  it  is  better  to  gulp  it  down 
quickly  than  to  hold  it  in  the  back  of  the  mouth,  dreading 
to  swallow  it. 

Peculiarities  of  the  Sense  of  Taste.  —  Taste  persists 
longer  than  most  of  the  other  sensations.  When  the 
light  ceases  to  shine  into  the  eye,  the  sense  of  sight  is 
gone ;  the  sense  of  sound  stops  when  the  vibration  that 
produced  it  no  longer  affects  the  ear.  The  sense  of  taste, 
however,  may  last  many  seconds,  or  many  minutes,  after 
the  substance  tasted  has  been  swallowed  ;  this  is  partly 


THE  PART   PLAYED  BY   THE  SPECIAL  SENSES     341 

because  small  particles  of  the  substance  remain  in  the 
mouth. 

The  sense  of  taste  is  quickly  tired.  Our  eyes  may  be 
used  all  day  long,  and  yet  we  see  as  clearly  at  night  as 
in  the  morning,  while  the  sense  of  taste  is  dulled  in  a  few 
minutes.  Even  if  we  eat  very  sparingly,  food  does  not 
have  such  a  pleasant  taste  at  the  close  of  a  meal  as  at  its 
beginning.  So  to  obtain  the  most  pleasure  from  the  sense 
of  taste  we  must  not  overgratify  it.  The  bulk  of  our 
food  should  be  such  as  satisfies  the  appetite.  Then  an 
occasional  luxury  that  gratifies  the  taste  will  be  more 
thoroughly  enjoyed.  Finely  flavored  substances,  like 
candies,  sauces,  and  sweets  in  general,  should  be  used  in 
comparatively  small  quantities.  This  results  not  only  in 
better  health,  but  also  in  greater  enjoyment  of  such 
delicacies.  Highly  flavored  food  at  every  meal  soon  ceases 
to  be  a  novelty.  The  most  delicious  foods,  if  constantly 
eaten,  soon  give  less  and  less  enjoyment. 


Smelling 

What  Smell  Is.  —  Only  substances  that  are  in  the  form 
of  gases  or  vapors  produce  the  sensation  of  smell.  We 
think  we  can  smell  a  liquid  like  strong  cologne,  but  the 
only  part  of  it  that  we  smell  is  the  vapor  rising  from  it. 
It  is  almost  unbelievable  how  small  an  amount  of  vapor 
is  required  to  excite  the  sense  of  smell ;  if  a  bottle  of  pep- 
permint oil  is  opened  for  a  few  moments,  it  gives  off  a 
vapor  that  fills  the  room.  Something  from  it  must  have 
passed  into  the  air  of  the  room.  Yet  if  the  bottle  is 
closed  again  and  reweighed  in  the  most  delicate  scales, 


342 


PHYSIOLOGY   AND    HEALTH 


there  is  no  perceptible  difference  in  its  weight.  No  other 
sense  is  as  delicate  as  that  of  smell.  With  some  animals 
this  sense  is  much  keener  than  in  human  beings.  How 
wonderfully  keen  it  must  be  in  the  dog  that  follows  his 
master's  footsteps,  even  through  a  crowded  thoroughfare, 

by  means  of  his  sense 
of  smell. 

Where  We  Smell. 
—  The  sense  of  smell 
is  located  in  the  nose. 
The  nostrils  lead  into 
two  large  cavities 
above  the  mouth, 
which  extend  back- 
ward to  the  throat, 
and  are  separated 

FIG.  93. -Section  through  the  nose,  showing  fr°m  6ach  °thei>  ^  E 

the    complex    air   passage.      O.n.,    olfactory  bony  partition.    These 

nerves;    Eu.,   opening  of  Eustachian  tube;  cavities       are       partly 

Pa.,  the  roof  of  the  mouth  (palate).  111 

filled  with  thin,  folded 

bones,  so  bent  around  as  to  form  curved  surfaces.  Upon 
these  bones,  especially  in  the  upper  part,  are  the  nerves  of 
smell  (olfactory  nerves),  as  shown  in  Figure  93.  Vapors 
entering  the  nose,  as  we  breathe,  act  upon  these  nerves  in 
such  a  way  that  they  send  messages  to  the  brain,  producing 
in  the  brain  the  sensation  that  we  call  odor  or  smell. 

The  acuteness  of  the  sense  of  smell  is  even  more  quickly 
blunted  than  the  acuteness  of  the  sense  of  taste.  The 
first  whiff  of  illuminating  gas  gives  a  strong  sensation,  but 
one  quickly  becomes  used  to  it.  For  this  reason  it  is 
foolish  to  sit  in  a  room  when  we  think  we  smell  gas. 


THE  PART  PLAYED  BY  THE  SPECIAL  SENSES    343 

Our  perception  of  the  odor  is  bound  to  grow  less  acute, 
so  we  should  heed  the  first  warning  of  danger  and  hunt 
for  the  source  of  the  odor. 

Touch  and  Temperature 

Sight,  hearing,  taste,  and  smell  are  very  distinct  senses. 
A  fifth  sense,  which  is  sometimes  called  the  sense  of  touch 
and  sometimes  given  the  more  general  name  of  feeling,  is 
really  made  up  of  several  different  kinds  of  sensations 
combined. 

The  Touch  or  Pressure  Sense.  —  The  nerves  in  the 
skin  are  very  sensitive  to  pressure.  When  anything 
presses,  even  very  lightly,  on  the  skin,  nervous  impulses 
are  sent  to  the  brain.  The  brain  interprets  them  and  gains 
from  the  sensation  some  knowledge  of  the  object  that  is 
touching  the  skin.  It  is  amusing  to  see  what  mistakes 
will  be  made  by  a  blindfolded  person  when  various 
familiar  objects  are  placed  in  his  hands  to  be  identified 
by  the  sense  of  touch  alone.  The  whole  skin  is  an  organ 
of  touch,  although  in  some  places  it  is  more  sensitive  than 
in  others. 

In  addition  to  the  sensation  that  the  skin  is  touched, 
we  know  too  with  considerable  accuracy  what  part  of 
the  body  is  being  pressed  upon  by  the  object  and  the 
amount  or  degree  of  pressure.  One  can  tell  whether  a 
penny  is  lying  on  the  palm  of  the  hand  or  on  one  of  the 
fingers.  The  sense  of  touch  is  most  delicate  at  the  tips  of 
the  fingers  and  at  the  tip  of  the  tongue.  We  can  locate 
within  a  twenty-fifth  of  an  inch  where  a  needle  point  touches 
the  skin  of  the  finger  tips  or  of  the  tongue.  On  the  back 
of  the  fingers  the  sense  of  location  is  much  less  delicate, 


344  PHYSIOLOGY   AND   HEALTH 

and  it  is  least  delicate  of  all  on  the  back,  at  the  shoulders ; 
in  fact,  we  cannot  determine  within  two  and  a  half  inches 
where  an  object  is  touching  the  back  of  the  shoulder. 

This  is  easily  tested  with  a  pair  of  dividers.  When 
you  are  blindfolded,  let  somebody  touch  your  cheek,  your 
finger  tips,  the  back  of  your  hand,  and  the  back  of  your 
neck,  sometimes  with  one  point  of  the  dividers  and  again 
with  both  points.  Notice  how  far  apart  the  points 
must  be  before  you  can  distinguish  whether  you  are  being 
touched  by  one  point  or  by  both  points.  We  can  see 
from  this  that  the  sense  of  touch  is  the  most  delicate  in 
those  parts  of  the  body  in  which  this  sense  is  most 
often  stimulated. 

The  delicacy  of  this  sense  increases  with  training,  as  is 
shown  by  the  fact  that  the  fingers  of  a  blind  man  become 
very  much  more  sensitive  than  those  of  a  man  v/ho  does 
not  have  to  depend  so  much  upon  touch  for  his  knowledge 
of  the  world.  From  the  sense  of  touch  and  from  our 
ability  to  locate  touch  sensations,  we  get  our  most  inti- 
mate knowledge  of  objects;  we  can  tell  whether  they 
are  rough  or  smooth,  blunt  or  sharp,  solid  or  liquid. 

The  Sense  of  Heat  and  Cold.  —  We  know  that  the 
sensation  of  being  hot  or  cold  is  due  to  tiny  organs  in  the 
skin,  which  feel  cold  or  hot  according  to  the  amount  of 
blood  flowing  over  them.  With  the  same  little  organs  we 
perceive  the  temperature  of  objects  that  touch  or  approach 
close  to  the  skin.  The  skin  in  general  is  sensitive  to  both 
heat  and  cold  though  some  spots  are  sensitive  to  heat  and 
not  to  cold,  others  to  cold  and  not  to  heat.  The  warm 
and  the  cold  "  spots  "  are  very  close  together,  so  that  we 
cannot  commonly  distinguish  them. 


THE  PART   PLAYED  BY  THE  SPECIAL  SENSES     345 

The  temperature  of  the  skin  is  not  the  same  at  all 
points;  we  know  that  if  the  hand  is  placed  on  the 
forehead,  the  forehead  feels  warm  to  the  hand  and  the 
hand  cool  to  the  forehead.  If  you  were  to  lay  on  a  boy's 
finger  a  metal  button  that  was  warmed  to  the  exact 
temperature  of  his  finger,  he  would  feel  the  pressure  of 
the  object,  but  it  would  give  him  no  sensation  either  of 
heat  or  of  cold. 

Our  idea  of  the  comparative  temperature  of  different 
objects  is  frequently  due  to  the  effect  they  produce  upon 
our  body  temperature.  In  cold  weather  we  would  rather 
jump  out  of  bed  onto  a  rug  than  to  step  onto  the  bare 
floor,  yet  floor  and  rug  are  exactly  the  same  temperature ; 
the  difference  is  that  the  bare  floor  draws  heat  away  from 
the  feet  more  rapidly  than  the  rug  does.  In  cold  weather, 
metal  objects  seem  colder  than  cloth  for  the  same  reason ; 
they  take  heat  away  from  the  body  more  rapidly. 

General  Sensations 

There  are  many  general  sensations,  all  of  which  tell  us 
something  about  the  condition  of  our  bodies.  One  of 
these  is  the  sense  of  hunger,  which  tells  us  that  we  need 
food.  We  feel  this  sensation  in  the  stomach,  and  it  dis- 
appears as  soon  as  we  give  the  stomach  food,  although,  as 
we  have  learned,  it  is  sure  to  be  a  long  time  before 
the  food  eaten  is  ready  to  nourish  the  body.  Thirst  is 
another  similar  sensation.  It  is  felt  in  the  throat  and 
disappears  as  soon  as  we  drink  sufficient  water. 

The  Sense  of  Pain.  —  Almost  any  nerve  that  carries 
impulses  to  the  brain  will  cause  a  sense  of  pain  if  it  is 
strongly  excited ;  pain  is  due  to  an  overstimulation  of  the 


346  PHYSIOLOGY   AND   HEALTH 

sensory  nerves.  We  can  determine  very  closely  the  loca- 
tion of  a  slight  pain,  but  not  so  readily  the  location  of  a 
severe  one.  A  slight  toothache  can  be  located  in  the  proper 
tooth,  but  a  severe  one  seems  to  come  from  the  entire 
jaw,  or  from  the  whole  side  of  the  head.  We  can  make 
a  slight  pain  seem  very  severe  by  allowing  ourselves  to 
think  of  it,  and,  on  the  other  hand,  many  of  our  pains 
disappear  if  we  try  to  forget  them  by  giving  our  atten- 
tion to  something  else.  This  is  what  is  meant  by  saying 
that  pain  is  largely  a  matter  of  the  imagination. 

Pain  always  has  some  meaning  for  us ;  it  is  usually  a 
warning.  The  sensible  thing  is  to  find  out  what  the  warn- 
ing means,  to  heed  it,  and  then  to  make  ourselves  think 
of  something  else.  People  who  do  not  understand  the 
meaning  of  pain  often  make  it  worse  by  rebelling  against 
it.  But  if  it  were  not  for  the  friendly  warnings  that  pain 
gives  us  we  should  probably  few  of  us  ever  live  to  grow  up. 
If  it  did  not  hurt  to  burn  the  fingers,  children  would  prob- 
ably entirely  destroy  their  fingers  before  they  were  old 
enough  to  know  how  to  take  care  of  them.  To  try  to  stop 
pain  by  using  a  "  pain  killer,"  or  any  drug  that  deadens 
it,  is  about  as  senseless  and  as  disastrous  in  its  results 
as  to  try  to  put  out  a  fire  by  stopping  the  fire  alarm  so 
that  we  shall  not  be  disturbed  by  it. 

The  Muscle  Sense.  —  There  is  a  sense  which  we  sel- 
dom recognize,  called  the  muscle  sense ;  by  it  we  know 
when  and  how  much  we  contract  our  muscles.  This  sense 
is  located  in  all  the  muscles,  but  especially  in  those  of  the 
joints.  With  closed  eyes,  we  can  move  our  fingers  an 
inch  or  a  foot,  whichever  we  wish,  knowing  almost  exactly 
how  much  the  muscles  are  contracting.  If  it  were  not 


THE  PART  PLAYED   BY  THE   SPECIAL  SENSES     347 

for  this  important  sense,  one  could  not  possibly  throw 
a  baseball  accurately  or  make  any  of  the  complicated 
body  motions  that  require  the  simultaneous  contraction 
of  a  large  number  of  muscles. 

Perhaps  you  did  not  know  that  you  had  such  a  sense. 
To  test  it,  rest  your  hand  on  a  table  and  close  your  eyes, 
and  see  if  you  can  tell  how  far  a  friend  lifts  your  hand. 
You  get  the  information  from  your  muscle  sense. 

QUESTIONS 

1.  Describe  the  structure  of  the  ear.     Could  one  hear  if  one  had 
no  outer  ear?    How  is  the  sensation  of  hearing  produced? 

2.  What  do  we  mean  by  sound?     How  does  sound  travel? 

3.  Have  you  ever  thrown  a  stone  into  still  water  and  watched  the 
ripples  of  water  that  travel  in  every  direction  from  the  spot  where  the 
stone  struck?    What  happens  in  the  air  when  a  sudden  explosion 
occurs  ? 

4;  Does  the  head  of  a  drum  vibrate  when  it  is  struck?  Why  can 
one  make  very  little  noise  with  a  drum  if  the  head  is  not  taut  ? 

5.  What  is  likely  to  happen  if  the  Eustachian  tube  gets  blocked 
up?    Why? 

6.  What  should  one  use  when  it  is  necessary  to  remove  wax  from 
the  ear? 

7.  What  may  result  from  trying  to  frighten  another  person  by 
making  a  loud  noise  near  his  ear?     Have  you  ever  heard  of  a  person 
being  deafened  by  a  Fourth-of-July  prank  ? 

8.  Name  the  most  frequent  cause  of  ear  troubles. 

9.  Where  are  the  sense  organs  of  taste?     Describe  them. 

10.  How  can  you  account  for  the  fact  that  alum  has  an  acid  taste 
when  placed  on  the  tip  of  the  tongue  and  a  sweetish  taste  when  pushed 
to  the  back  of  the  tongue? 

11.  Explain  why  one  who  likes  his  food  highly  seasoned  with  salt 
and  pepper  would  have  to  keep  using  more  and  more  of  these  condi- 
ments as  time  went  on. 


348  PHYSIOLOGY   AND    HEALTH 

12.  Chew  some  pure  roasted  coffee,  holding  the  nose  as  you  do  so. 
Then  chew  some  without  holding  the  nose  and  notice  the  difference  in 
its  taste. 

13.  Where  is  the  sense  organ  of  smell  located? 

14.  Describe  how  it  is  stimulated. 

15.  Do  you  think  it  is  very  important  that  one's  sense  of  smell 
should  be  acute?    Cite  instances  to  prove  it. 

16.  A  hunter  when  he  is  tracking  an  animal,  approaches  from  the 
opposite  direction  from  which  the  wind  blows.     Explain  why. 

17.  Think  of  some  experiment  by  which  you  can  prove  that  cold, 
heat,  and  pressure  are  not  felt  by  the  same  end  organs. 

18.  What  parts  of  the  body  are  most  sensitive  to  touch?    Which 
are  the  least  sensitive?    Can  you  see  any  reason  why 'nature  has 
provided  that  the  tips  of  the  fingers  and  the  lips  should  be  especially 
sensitive  ? 

19.  Name  some  of  the  sensations  we  classify  as  "general."    Why 
is  it  both  senseless  and  dangerous  to  take  medicines  to  deaden  pain? 


SECTION  IV 
PERSONAL  AND   PUBLIC   HEALTH 

CHAPTER   I 
THE  CAUSES  OF  ILL  HEALTH 

Our  First  Duty  to  Keep  Well.  —  To  be  in  health  means 
that  all  of  the  many  organs  of  the  body  are  running 
smoothly  and  doing  their  proper  work.  One  is  not  in 
health  if  his  heart  is  working  well  but  his  digestive  organs 
badly,  or  if  his  digestive  organs  are  in  good  condition 
but  his  brain  is  not  thinking  true.  Many  people  con- 
sider a  person  well  if  his  general  body  functions  are  car- 
ried out  properly,  even  though  his  mind  is  so  disjointed 
that  he  does  not  tell  the  truth,  and  he  is  unable  to  con- 
trol his  passions  ;  but  that  is  not  perfect  health.  Health 
means  a  sound  mind  in  a  sound  body. 

A  person  who  frequently  has  to  give  up  work  because 
he  is  ill  rarely  accomplishes  much  that  is  satisfactory 
to  himself  or  to  others,  and  he  surely  does  not  have 
much  pleasure.  In  these  days  we  hear  much  about 
efficiency.  Efficiency  means  simply  the  ability  to  do 
what  you  undertake  to  do  in  the  best  way.  It  means 
getting  the  largest  possible  results  with  the  least  effort 
and  the  smallest  amount  of  waste.  A  boy  or  a  girl,  or 
a  man  or  a  woman,  who  can  accomplish  the  most  with 

349 


350  PHYSIOLOGY   AND   HEALTH 

the  powers  that  he  has  will  be  the  happiest.  But  he 
can  do  this  only  provided  he  is  well  three  hundred  and 
sixty-five  days  in  the  year. 

To  keep  well  is  the  normal  condition  of  life.  There 
are  in  the  United  States  at  all  times,  some  3,000,000 
people  on  the  sick  list,  capable  of  doing  nothing  to  satisfy 
themselves  or  their  friends.  And  yet  a  large  part  of 
this  sickness  is  wholly  unnecessary.  These  wonderful 
bodies  of  ours,  if  properly  treated,  will  run  regularly, 
and  adapt  themselves  to  the  many  different  kinds  of 
lives  that  we  have  to  live,  and  to  the  different  things  that 
we  have  to  do.  If  you  give  your  body  a  chance,  it  will 
continue  to  be  well  and  strong,  and  ready  to  do  your 
bidding  for  many  years. 

If  we  do  not  take  proper  care  of  an  automobile,  some- 
thing is  sure  to  happen  to  it.  We  find  some  day  that 
it  does  not  run  properly ;  it  will  not  climb  hills,  it  runs 
with  irregular  jerks  or  even  refuses  to  go  at  all.  Be- 
cause we  have  neglected  it  something  has  gone  wrong 
with  the  machinery.  Neither  will  our  automobile  work 
well  if  the  chauffeur  does  not  know  how  to  drive  it.  A 
good  driver  can  get  much  more  work  out  of  it  than  can 
a  bad  one.  Our  bodies  are  better  able  to  take  care  of 
themselves  than  is  an  automobile,  and  indeed  will  stand 
much  ill  treatment  without  making  a  protest.  But 
when  we  do  become  ill,  we  may  be  sure  it  is  a  protest  of 
the  body  against  some  kind  of  bad  treatment. 

The  Causes  of  111  Health.  —  Since  health  is  the  normal 
condition  of  life,  there  must  be  a  reason  for  every  case 
of  ill  health,  even  though  we  may  not  always  be  able  to 
discover  what  it  is.  Scientists  and  doctors  tell  us  that 


THE   CAUSES   OF   ILL   HEALTH  351 

there  are  two  different  types  of  influences  that  cause 
ill  health. 

1.  Wrong  habits  of  life. 

2.  Tiny  parasites  that  get  into  the  body  and  produce 
trouble,  i.e.  germs. 

While  these  two  causes  of  ill  health  are  quite  different, 
in  many  cases  of  illness  they  occur  together.  If  by  good 
habits  we  can  only  succeed  in  keeping  our  bodies  strong 
and  vigorous,  they  have  great  powers  of  resisting  the 
attacks  of  parasites.  Many  a  time  it  has  happened  in 
the  lives  of  each  one  of  you  that  some  of  these  tiny  foes 
have  found  entrance  into  the  body,  through  the  nose, 
the  mouth,  through  a  cut  in  the  skin,  or  otherwise,  but 
they  have  been  %  quickly  driven  out  again  or  killed  by  the 
resisting  powers  of  the  body.  You  have  not  even  been 
conscious  that  you  have  had  any  trouble  at  all.  Good 
habits  of  life  lead  to  strength  and  vigor,  and  these  con- 
stitute the  best  protection  against  germs.  On  the  other 
hand,  bad  habits,  by  weakening  our  bodies,  have  the 
same  effect  that  weakening  the  fortifications  of  a  town 
has.  They  prevent  our  successfully  resisting  the  attack 
of  enemies  (germs)  that  have  had  an  opportunity  to 
attack  us.  By  strengthening  our  defenses  we  may  resist 
their  attack. 

Some  Reasons  Why  Animals  Keep  Well.  —  Did  you 
ever  hear  of  wild  animals  being  sick?  It  is  true  that 
they  are  sick  occasionally,  but  it  is  a  rare  occurrence, 
and  always  means  that  something  unusual  has  happened 
in  their  lives.  With  human  beings  it  is  not  so  uncommon 
to  be  ill.  But  here  too  it  means  that  something  unusual 
and  unfortunate  has  happened  in  their  lives.  Sometimes 


352 


PHYSIOLOGY   AND    HEALTH 


the  trouble  is  unavoidable,  but  frequently  it  is  due  to 
ignorance  or  thoughtlessness,  or  even  unwillingness  to 
do  what  one  knows  to  be  right  and  wise.  It  is  to  prevent 
our  making  such  mistakes  from  ignorance  that  we  study 
physiology.  It  is  to  prevent  our  making  such  mistakes 
from  thoughtlessness  that  various  rules  of  health  are  so 
frequently  emphasized.  We  are  very  much  wiser  than 

wild  animals  are,  and  we 
certainly  ought  to  learn 
how  to  keep  as  well  as 
they  do. 

We  may  gain  some 
useful  information  by 
noting  some  of  the  rea- 

FIG.  94.  -THE  DOMESTICATED  HOG. 


gons      wfry     animals     are 

rarely  sick.  In  the  first  place,  we  may  remember  that 
they  do  not  make  judgments  about  things  as  we  do.  They 
act  from  instinct  ;  and  instinct  usually  tells  them  what 
to  eat  and  how  to  live.  We  do  not  have  such  instincts, 
and  it  takes  us  years  to  learn  the  same  lessons.  Our 
wonderful  minds  make  us  more  powerful  than  animals, 
and  enable  us  to  do  many  things  that  they  cannot  do. 
But  sometimes  our  minds  lead  us  astray,  and  cause  us 
to  acquire  habits  that  are  unfortunate. 

Animals  Eat  the  Food  They  Need.  —  For  wild  animals, 
food  is  almost  always  scarce,  and  much  of  their  time  is 
spent  in  hunting  for  it.  They  eat  it  just  as  they  find 
it  ;  they  do  not  have  any  way  of  preparing  it  so  as  to 
make  it  taste  better.  They  do  not  have  a  sweet  dessert 
or  candy  to  tempt  them  to  eat  after  their  appetite  is  satis- 
fied. For  these  reasons,  animals  in  the  natural  state 


THE   CAUSES  OF   ILL  HEALTH  353 

are  not  likely  to  eat  too  much.  Sometimes  we  tempt  our 
domestic  animals  to  eat  more  than  they  need.  Notice 
what  effect  overfeeding  has  had  upon  the  hog.  We 
furnish  him  with  large  quantities  of  food  of  which  he  is 
very  fond.  He  becomes  fat  and  sluggish,  and  good  for 
nothing  except  to  eat  and  to  be  eaten.  A  fattened  hog 
is  subject  to  many  diseases.  The  wild  hog  does  not 
get  much  food,  does  not 
become  fat,  and  does  not 
become  sick. 

Contrast  this  with  our 
own  food  habits.  If  we 
ate  our  foods  as  nature 
furnishes  them,  we  should 
probably  not  eat  more 
than  we  require.  But  FlG'  95'  ~  THE  WlLD  HOG' 

we  prepare  our  food  artificially  in  such  a  way  as  to  in- 
crease the  pleasure  of  eating.  Flour  is  made  to  look  white 
and  more  attractive  by  removing  some  of  its  useful  parts. 
Sugar  is  removed  from  the  sugar  cane  or  the  sugar  beet, 
and  concentrated,  so  that  it  may  be  even  more  sweet,  and 
then  we  add  delicious  flavors  to  produce  confectionery. 
Flavors  in  infinite  variety  are  brought  from  all  parts  of 
the  world  and  added  to  our  foods  to  give  them  a  more 
attractive  taste.  This  has  one  effect  upon  children  and 
grown  people  alike.  It  leads  us  to  eat  because  we  like 
the  taste  of  our  food  rather  than  because  we  are  hungry. 
Consequently  we  frequently  eat  too  much,  and  the  ex- 
cess of  food  makes  us  sleepy  and  inactive,  leads  to  a 
sluggish  and  unhealthful  life,  and  tends  to  an  unhealthful 
accumulation  of  fat. 


354  PHYSIOLOGY   AND   HEALTH 

Animals  Are  Active.  —  Most  wild  animals  have  to 
hunt  for  their  food ;  food  is  never  brought  to  them. 
This  forces  them  to  live  an  active  life,  perhaps  traveling 
long  distances  and  running  rapidly  in  order  to  capture 
the  food  they  need.  The  result  is  that  they  have  no 
chance  to  get  fat  and  sluggish  and  that  they  have  well- 
developed  muscles. 

Very  few  people  live  a  life  as  active  as  wild  animals  are 
obliged  to  live.  We  have  learned  how  the  hermit  crab 
lost  his  shell  when  he  ceased  to  use  it.  This  is  only  one 
illustration  of  a  general  law :  any  power  that  we  cease 
to  use  becomes  weaker  and  may  finally  disappear.  Our 
left  hand  is  weaker  than  our  right  because  it  is  used  less. 
We  noticed  in  an  earlier  chapter  how  various  sets  of 
muscles  are  shielded  from  use  because  we  patronize 
trolley  cars,  elevators,  automobiles,  etc.  These  inven- 
tions of  our  minds  deprive  us  of  the  use  of  our  bodies. 

The  inactive  kind  of  life  which  you  are  likely  to  adopt 
after  you  grow  older,  unless  you  are  careful  to  avoid  it, 
leads  to  quiet  breathing  that  never  completely  fills  the 
lungs  and  in  time  causes  them  to  become  incapable  of 
proper  expansion.  It  also  weakens  the  heart.  To  be 
sure,  the  heart  never  stops  beating ;  but  to  keep  it  strong 
and  ready  to  respond  to  a  sudden  need,  we  must  give  it 
occasionally  more  than  its  ordinary  amount  of  work 
to  do.  When  we  run,  climb  hills,  or  do  any  other  kind 
of  hard  work,  the  heart  has  to  work  harder  and  faster. 
You  know  how  you  can  feel  your  heart  beat  after  a 
run.  This  kind  of  life  strengthens  the  heart  and  in- 
vigorates the  circulation.  The  heart  so  trained  is  ready 
to  meet  any  sudden  demand  put  upon  it,  as  for  example 


THE   CAUSES  OF   ILL  HEALTH  355 

when  one  is  obliged  to  run  to  catch  a  train;  while  if  one 
has  lived  a  quiet  life,  his  heart  may  utterly  fail  him  at 
the  crisis  if  it  is  suddenly  called  upon  to  do  unusual 
work. 

The  skin  also  suffers  from  lack  of  use.  We  cover  our 
bodies  with  clothing,  whereas  animals  do  not.  To  be 
sure,  many  animals  are  covered  with  fur  in  place  of  cloth- 
ing ;  but  we  must  remember  that  they  cannot  take  their 
fur  off  and  put  it  on  as  we  do  our  clothes.  Under  these 
circumstances  the  skin  learns  to  adapt  itself  to  any 
change  in  temperature  that  may  occur  in  the  climate  where 
they  live.  The  skin  of  our  faces  and  hands  gets  plenty  of 
exercise  of  this  sort  and  soon  learns  to  adapt  itself  to 
variations  in  temperature.  This  power  becomes  so  well 
developed  that  we  little  mind  the  cold  in  winter  when  it 
strikes  our  hands  and  faces.  They  tingle  a  bit,  but  they 
soon  glow  with  a  vigorous  flow  of  warm  blood.  The  rest 
of  the  skin  is  kept  so  carefully  covered  that  it  has  no 
opportunity  to  get  the  needed  exercise.  We  keep  the 
surface  of  the  body  covered  so  constantly  that  the  skin 
actually  lives  at  a  temperature  of  eighty  degrees  even  in 
cold  weather.  So  seldom  is  the  skin  called  upon  to  re- 
spond to  the  stimulus  of  a  little  cold  air  that  it  forgets 
how  to  respond,  or  perhaps  never  learns,  and  all  of  our 
lives  we  suffer  from  it.  We  attribute  the  numerous 
colds  that  we  have  to  cold  drafts,  quite  forgetful  of  the 
fact  that  we  never  have  given  the  skin  an  opportunity 
to  get  accustomed  to  such  changes.  Perhaps  then  we 
bundle  up  even  more  warmly,  thinking  that  we  can 
thus  remedy  the  tendency  to  take  cold.  But  this  only 
weakens  the  skin  more  by  giving  it  still  less*  to  do.  A 


356  PHYSIOLOGY   AND    HEALTH 

better  remedy  is  to  use  it,  not  to  protect  it  from  use.  Like 
the  muscles,  the  skin  increases  in  its  power  as  it  is  used. 
Cold  baths,  air  baths,  vigorous  rubbing,  are  measures  by 
which  all  young  people  can  soon  bring  the  skin  into  a 
vigorous  condition,  which  will  enable  them  to  forget 
how  to  take  cold. 

Animals  Live  Out  of  Doors.  —  People  are  almost  the 
only  animals  that  pass  much  of  their  time  indoors.  To 
be  able  to  shelter  ourselves  from  cold  and  storm  so  that 
we  may  live  in  all  kinds  of  climates  is  one  of  the  triumphs 
of  the  human  mind.  But  with  all  the  advantages  of  our 
homes,  animals  living  out  of  doors  are  in  some  respects 
better  off  than  those  that  live  in  closed  houses.  Fresh 
air  is  needed  to  keep  the  blood  pure,  and  cold  air  is  a 
stimulus  that  will  keep  the  lungs  and  the  air  passages 
active  and  healthful.  By  a  life  out  of  doors,  animals 
become  fitted  for  the  climate  in  which  they  live.  People 
do 'not  become  particularly  fitted  for  any  climate.  In- 
deed, they  try  to  live  in  two  climates  at  once,  one  of 
which  is  indoors  and  the  other  out  of  doors ;  one  that 
has  a  temperature  of  seventy  or  sometimes  even  eighty, 
while  the  other  may  be,  in  winter,  near  to  zero.  We  have 
not  succeeded  in  fitting  ourselves  for  both  climates,  and 
as  a  result  life  indoors  brings  upon  us  quite  a  considerable 
part  of  our  illnesses. 

Animals  Take  Plenty  of  Sleep.  —  Did  you  ever  notice 
how  much  of  his  time  a  dog  spends  in  sleep?  The  same 
thing  is  true  of  nearly  all  other  animals.  This  is  doubt- 
less one  of  the  reasons  why  animals  keep  so  well.  When 
you  were  small  you  also  slept  all  that  you  needed.  But 
as  you  have  begun  to  learn  ways  of  enjoying  yourself  you 


THE   CAUSES   OF   ILL  HEALTH 


357 


sometimes  prefer  pleasure  to  sleep.  You  are  tempted 
to  stay  up  later  and  later,  the  excitement  of  the  moment 
making  you  forget  you  are  sleepy.  Nevertheless  it  is 
true  that  the  late  hours  lessen  your  efficiency  and  injure 
your  health,  and  your  enjoyment  as  well,  since  a  moderate 
amount  of  enjoyment  with  plenty  of  sleep  is  far  more 
pleasurable  than  continued  dissipation  kept  up  until 
the  late  hours  of  night. 

Handicaps.  —  If  you  should  start  to  run  a  race  and 
should  deliberately  put  on  a  pair  of  heavy  shoes,  or  a 
pair  of  shoes  with  lead  in  the  heels,  we  should  regard 
you  as  excessively 
foolish.  We  should 
say  that  you  had  so 
handicapped  your- 
self that  there  was 
no  hope  of  your  win- 
ning in  the  race. 
You  certainly  would 
not  be  foolish 
enough  to  do  this. 
But  many  a  boy  and 

girl  just  starting  to  run  the  race  of  life  does  exactly 
this  same  thing.  If  you  will  for  a  moment  think 
over  some  of  the  habits  which  are  mentioned  in  the 
chapters  in  this  book,  you  will  easily  see  what  some  of 
these  handicaps  are,  and  you  can  tell  whether  you  have 
been  foolish  enough  to  burden  yourself  with  any  of  them. 
If  you  are  wise,  you  will  try  to  discover  what  they  are, 
and  to  overcome  them.  What  are  some  of  the  handi- 
caps with  which  boys  and  girls  that  you  know  have 


FIG.  96.  —  WHICH  BOY  WILL  PROBABLY  WIN  ? 


358  PHYSIOLOGY   AND   HEALTH 

burdened  themselves?  Have  you  not  some  that  you 
would  like  to  get  rid  of? 

Personal  Hygiene  not  a  Popular  Subject.  —  We  have 
various  public  officials  in  our  community  whose  duty  it 
is  to  look  after  matters  connected  with  public  health, 
but  there  are  none  who  consider  it  their  duty  to  do  any- 
thing toward  improving  the  habits  of  living  of  the  people, 
so  as  to  reduce  the  amount  of  ill  health  that  is  due  to 
incorrect  living.  For  some  strange  reason  most  people 
object  to  having  others  tell  them  how  they  ought  to 
live. 

Perhaps  this  is  because  in  following  the  rules  of  personal 
hygiene  we  are  required  to  make  sacrifices.  We  may 
have  to  give  up  eating  quite  as  much  as  we  like  and  to 
deny  ourselves  quite  so  many  sweet  dainties.  We  may 
have  to  put  on  some  sensible  shoes,  in  place  of  the  tight- 
fitting,  high,  French-heeled  shoes,  which  look  well  but 
feel  so  uncomfortable.  It  may  be  necessary  for  us  to  give 
up  staying  out  late  at  night  and  thus  continually  depriving 
ourselves  of  our  needed  sleep.  Perhaps  we  shall  have  to 
give  up  some  of  the  time  we  spend  in  easy  chairs  and  spend 
more  time  in  actively  using  our  muscles.  All  of  this 
means  work,. and  with  our  love  for  ease  we  do  not  enjoy 
being  told  of  these  things.  But  if  we  could  only  be- 
lieve it,  we  shall  really  get  a  great  deal  more  pleasure 
out  of  life  if  we  will  do  these  very  things.  The  sweet 
dainties  will  actually  taste  better  to  us  if  we  do  not  eat 
many,  just  as  the  little  candy  that  the  poor  boy  has  as 
a  rare  treat  tastes  much  better  to  him  than  it  does  to 
the  rich  boy  who  has  all  he  wants.  An  evening  of  pleas- 
ure is  much  more  enjoyed,  and  the  following  day  is  enjoyed 


THE  CAUSES  OF  ILL  HEALTH  359 

much  better  also,  if  we  do  not  turn  night  into  day  and 
keep  up  the  night's  pleasures  until  morning.  Just  as 
soon  as  we  make  the  experiment,  we  find  that  when 
we  have  filled  our  lives  with  good  habits  in  the  place  of 
bad  ones,  we  have  filled  our  lives  at  the  same  time  with 
much  greater  happiness  and  contentment.  Above  all 
things,  we  shall  have  better  health,  and  more  strength 
to  do  the  things  that  are  worth  while.  Hygiene  cer- 
tainly does  ask  us  to  give  up  some  things,  but  it  offers 
in  their  place  much  that  is  far  better. 

Since  personal  hygiene  concerns  the  individual,  and 
does  not  seem  to  have  anything  to  do  with  the  public, 
we  have  usually  not  considered  it  necessary  to  have  public 
officials  pay  any  attention  to  it.  If  some  one  should  have 
smallpox,  the  public  officials  would  attend  to  the  matter 
at  once,  to  protect  the  public  from  the  disease ;  but  if  a 
person  ruins  his  digestion  by  improper  eating,  no  one  con- 
siders it  his  business  to  interfere.  If  a  boy  wants  to 
injure  his  chances  for  life  by  smoking  cigarettes,  or  a  girl 
is  willing  to  undermine  her  digestion  by  eating  too  much 
confectionery,  it  has  been  thought  that  it  is  no  one's 
business  but  their  own,  and  possibly  that  of  their  parents. 
But  people  are  beginning  to  feel  to-day  that  perhaps  after 
all  it  is  as  much  a  public  duty  to  protect  children  from 
acquiring  bad  habits  as  it  is  to  protect  them  from  ac- 
quiring dangerous  germs.  Surely  health  is  as  important 
11.3  education.  Perhaps  the  time  will  come  when  it  will 
bs  regarded  as  a  disgrace,  not  merely  a  misfortune,  to 
be  sick,  for  it  will  be  realized  that  sickness  is  due  either 
to  wrong  habits  or  to  an  insufficient  protection  of  the 
individual  against  dangerous  disease  germs. 


360  PHYSIOLOGY   AND   HEALTH 

QUESTIONS 

1.  Why  is  it  sometimes  a  disgrace  for  one  to  be  sick? 

2.  Give  the  reasons  why  wild  animals  are  rarely  sick. 

3.  Why  do  wild  animals  not  overeat? 

4.  Can  you  explain  why  a  laborer  is  less  likely  to  have  heart  disease 
than  a  banker? 

5.  In  what  sense  is  a  cold  bath  good  gymnastics  for  the  skin  ? 

6.  Why  do  soldiers  and  sailors  seldom  take  cold  ? 

7.  Do  you  know  of  any  examples  of  grown  people  who  have  lost 
some  of  their  powers  by  failing  to  use  them  ? 

8.  Give  six  common  handicaps  that  stand  in  the  way  of  health. 

9.  Why  do  not  public  health  officers  look  after  personal  health  as 
well  as  public  health? 


CHAPTER   II 
HEALTH    HABITS  AND   OCCUPATIONS 

ONE'S  health  and  happiness  in  life  are  determined  very 
largely  by  the  choice  of  an  occupation.  There  are  some 
occupations  that  are  very  dangerous  to  health  and  life. 
Men  are  usually  obliged  to  engage  in  occupations  that 
are  more  dangerous  than  those  that  are  followed  by 
women.  But  of  them  some  are  much  more  dangerous 
than  others.  Employment  on  railroads  and  trolley  cars, 
or  any  work  that  keeps  one  on  the  streets  of  large  cities, 
offers  dangers  of  accident,  as  do  occupations  requiring 
the  handling  of  powerful  or  rapidly  moving  machinery. 
Mining,  bridge  building,  the  construction  of  large 
buildings  or  tunnels,  offer  special  dangers.  Working  in 
an /impure  atmosphere  is  dangerous,  this  being  partic- 
ularly true  of  occupations  that  involve  the  use  of  grind- 
stones, from  which  minute  particles  of  metal  and  dirt 
are  thrown  off  into  the  air ;  or  in  factories  where  minute 
fibers  of  cotton  or  wool  are  thrown  from  machines  into 
the  air  that  workmen  must  breathe.  Any  occupation 
that  keeps  one  constantly  within  doors,  like  that  of 
clerks  in  stores  or  in  offices,  invites  tuberculosis,  because 
of  the  lack  of  fresh  air  and  proper  exercise.  It  may 
not  be  possible  or  desirable  in  choosing  your  occupation 
to  avoid  all  that  are  dangerous.  But  when  one  is  choosing, 
one  should  always  consider  carefully  the  question  of 

361 


362  PHYSIOLOGY   AND   HEALTH 

the  healthfulness  of  the  occupations  that  are  open  to 
him,  and  should  choose  the  most  healthful,  even  though 
it  offers  less  in  the  way  of  compensation.  For  while  the 
money  returns  may  be  less,  healthful  occupations  will 
surely  offer  greater  returns  in  the  way  of  happiness. 
One's  happiness  in  life  depends  upon  health,  and  not 
upon  the  amount  of  money  that  may  be  earned.  Indeed, 
as  a  rule,  the  amount  of  money  that  one  may  earn 
depends  chiefly  upon  his  health,  for  ill  health  is  always 
accompanied  by  reduced  earning  capacity.  If  you  neg- 
lect your  health,  you  will  soon  be  unable  to  earn  as 
much.  Ill  health  and  poverty  commonly  go  together. 
The  first  thing  to  think  of,  in  planning  one's  life,  is  health 
and  strength,  and  not  the  amount  of  money  that  may  be 
earned. 

"  Safety  Fkst."  —  But  there  are  many  dangerous 
occupations  which  must  have  their  employees,  and  there 
are  plenty  of  people  who  are  willing  to  engage  in  them 
if  a  little  more  money  may  be  earned.  Many  of  these 
special  dangers  may  be  guarded  against  and  largely 
lessened  by  adopting  certain  precautions.  For  example, 
the  special  dangers  in  the  grinding  trade  may  be  in  a 
measure  avoided  by  the  use  of  suction  fans,  which  re- 
move the  dust-laden  air  and  supply  purer  air  to  breathe. 
Similar  precautions  may  be  adopted  in  other  occu- 
pations. "  Safety  first  "  has  become  the  motto  of 
many  industries  and  the  foundation  of  many  laws.  As 
employers  are  sometimes  unwilling  to  spend  the  money 
necessary  for  such  precautions,  the  state  finds  it  neces- 
sary to  step  in  and  to  enact  laws  requiring  safety  devices 
which  lessen  the  dangers  from  some  of  these  occupations, 


HEALTH   HABITS  AND   OCCUPATIONS  363 

and  also  to  appoint  officials  to  see  that  these  laws  are 
enforced.  The  workingmen  alone  are  usually  unable  to 
secure  this  protection,  and  their  safety  requires  the  aid 
of  public  officials  backed  by  law.  Some  states  require 
employers  to  insure  their  workingmen,  so  that  if  in- 
jured in  their  employ,  an  employee  may  be  guaranteed 
compensation  for  the  time  lost,  or  if  he  dies  his  family 
may  get  the  insurance. 

Wholesome  Vacation  Plans.  —  During  the  school  year 
much  of  the  time  every  day  must  be  spent  in  the  school- 
room, and  your  occupations  out  of  school  must  not  be  such 
as  to  interfere  with  a  regular  attendance  at  school. 
But  when  vacation  comes  there  are  many  days  together 
in  which  you  can  follow  any  chosen  path  of  life.  How  to 
spend  a  vacation  is  a  question  that  is  asked  over  and 
over  again,  usually  for  the  purpose  of  getting  the  greatest 
amount  of  pleasure  rather  than  the  greatest  amount 
of  good  out  of  it.  Fortunately  it  happens  that  many 
kinds  of  vacations  give  not  only  the  greatest  amount  of 
pleasure  but  also  the  largest  amount  of  health  and 
strength. 

It  is  impossible  to  give  any  suggestions  for  vacations 
spent  in  the  country  that  will  fit  the  life  and  tastes  oft 
all.  One  thing,  however,  every  one  should  remember. 
The  best  kind  of  vacation  is  one  that  keeps  you  out  of 
doors  the  largest  amount  of  the  time.  If  you  are  able  to 
go  camping,  or  to  take  frequent  walks  through  the  country, 
you  can  hardly  improve  upon  such  a  method  of  spending 
your  vacation.  If  you  are  fortunate  enough  to  be  able 
to  spend  your  vacation  in  the  country,  it  can  give  you 
an  endless  amount  of  pleasure.  Learn  the  names  of 


364 


PHYSIOLOGY   AND    HEALTH 


common  flowers,  and  learn  to  know  the  common  birds. 
See  how  many  kinds  of  ferns  you  can  discover  growing 
by  the  roadside,  or  how  many  kinds  of  trees  in  the  forest 
near  by.  It  is  interesting,  too,  to  see  how  many  kinds  of 
grasses  you  can  find  growing  in  the  fields.  One  of  the 


FIG.  97.  —  You  CAN  HARDLY  IMPROVE  UPON  THIS  METHOD  OF  SPENDING 

A  VACATION. 

most  attractive  kinds  of  hunting  in  the  summer  is  to  see 
how  large  a  variety  of  toadstools  you  can  discover  in 
the  woods.  You  do  not  need  to  learn  their  names,  but 
simply  to  recognize  them.  They  are  mostly  so  different 
from  one  another  that  there  will  be  no  difficulty  in  telling 
them  apart.  There  is  really  much  more  pleasure  in 
this  kind  of  stroll  through  the  woods  than  in  hunting  for 


HEALTH   HABITS  AND  OCCUPATIONS 


365 


and  killing  birds  and  wild  animals.  It  is  much  more  fun 
to  photograph  a  living  bird  than  to  shoot  it.  By  all 
means  get  into  the  country  during  the  vacation  if  you 
can. 

Perhaps,   however,   you  must  pass  your  vacation  in 
a  city.     You  should  then  try  to  find  some  kind  of  outdoor 


FIG.  98.  —  A  CITY  PLAYGROUND. 

sport  that  will  interest  you.  Very  likely  there  are  city 
playgrounds.  Boys  and  girls  using  them  think  of  them 
simply  as  places  where  they  may  enjoy  themselves,  and 
never  as  a  means  of  keeping  health.  In  large  cities  the 
streets  cannot  well  be  used  as  playgrounds,  and  there  is 
therefore  a  tendency  to  keep  children  indoors  so  as  to 
avoid  the  dangers  of  the  street.  But  it  takes  out- 


366 


PHYSIOLOGY   AND   HEALTH 


door  games  to  develop  muscles,  lungs,  quickness  of  think- 
ing, and  general  strength  and  vigor.  The  playground 
which  attracts  boys  and  girls  to  outdoor  games  gives 
to  city  children  a  little  of  the  kind  of  life  that  the 
country  child  has.  It  gives  them  a  strong  invitation  to 
live  and  exercise  in  the  open  air  during  the  summer.  If 


FIG.  99.  —  SPEND  SOME  OF  YOUR  VACATION  IN  LEARNING  TO  SWIM. 

there  is  a  playground  near  where  you  live,  you  will  find 
plenty  of  others  to  join  with  you  in  the  games,  perhaps 
baseball,  basket  ball,  or  tennis,  or  some  other  of  the 
outdoor  sports  that  are  common  in  playgrounds.  Join 
some  athletic  club  if  you  can,  for  the  games  will  be  more 
interesting  and  hence  more  useful  if  you  engage  in  con- 
tests between  club  teams.  Such  advice  applies  to  girls 


HEALTH  HABITS  AND  OCCUPATIONS  367 

as  well  as  to  boys,  and  should  be  even  more  emphasized 
in  the  case  of  girls  because  they  are  not  so  likely  to  follow 
it. 

By  all  means  spend  some  of  the  vacation  in  learning  to 
swim.  If  you  search  for  it,  you  probably  can  find  some 
opportunity  near  you,  either  in  a  river  or  lake,  or  in 
public  baths. 

Above  all  things,  the  vacation  should  mean  a  life  of 
activity  out  of  doors  every  possible  moment,  full  of  sports, 
and  real  happy  companionship.  Vacation  time  is  the  time 
when  you  should  build  up  strong  muscles,  get  rosy  cheeks, 
and  cultivate  a  contented  mind,  which  will  undertake 
the  duties  of  school  life,  when  the  vacation  is  over,  with 
willingness  and  eagerness. 

Accidents 

You  have  surely  seen  some  men  and  probably  some 
boys  who  have  been  permanently  injured  by  accidents. 
The  accident  may  have  resulted  in  the  loss  of  a  finger  or 
perhaps  an  arm  or  a  leg,  or  it  may  have  caused  permanent 
lameness  or  some  other  disability.  If  a  crab  loses  a  leg, 
a  new  one  will  grow ;  but  a  boy,  if  so  injured,  must  carry 
his  injury  through  life. 

Some  accidents  are  unavoidable  and  are  liable  to  come 
to  any  one.  But  many  of  them  are  needless  and  will 
not  occur  to  one  who  is  reasonably  careful.  A  large 
majority  come  from  carelessness  and  thoughtlessness. 
"  Safety  first  "  is  the  motto  that  every  boy  and  girl 
should  fix  firmly  in  mind.  "  Taking  a  dare  "  is  one  of 
the  follies  that  boys  sometimes  indulge  in.  It  is  folly 
because  it  usually  means  taking  useless  risks  or  running 


368 


PHYSIOLOGY  AND   HEALTH 


FIG.  100.  —  THE  RIGHT  WAY 
TO  GET  OFF  A  CAB. 


into  useless  dangers  for  no  purpose  except  that  another 
"  dares  "  you.     The  really  brave  boy  is  the  one  who  is 

brave  enough  to  say,  "  I  am  not 
going  to  be  dared  into  useless 
dangers." 

Accidents  to  children  playing 
in  the  city  streets,  and  now  that 
automobiles  are  so  common,  in 
the  country  roads  as  well,  are 
common.  They  are  usually  due 
to  the  carelessness  of  the  children 
themselves.  No  matter  how 
careful  the  motorman  of  a  trolley 
car  or  the  driver  of  an  automobile  may  be,  he  cannot  al- 
ways prevent  an  accident  if  children  run  out  into  the 
street  in  front  of  his  car.  So 
when  playing  in  the  streets,  al- 
ways bear  in  mind  that  before 
you  cross  after  your  ball,  you 
must  look  carefully  in  both 
directions  to  see  if  there  is  dan- 
ger. When  getting  off  a  trolley 
car  always  face  toward  the  front. 
If  you  face  backwards  any  mo- 
tion of  the  car  will  be  likely  to 
throw  you  down.  If  you  are 
crossing  the  street  in  front  of 
or.  behind  a  car  that  is  standing  still,  be  particularly 
careful  before  stepping  out  from  behind  it  to  see  that 
no  trolley  or  automobile  is  coming  along  on  the  other 
side.  Keep  both  eyes  and  ears  constantly  open  all  the 


FIG.  101.  — TAKING    Too    Bu; 
A  CHANCE. 


HEALTH   HABITS  AND  OCCUPATIONS  369 

time  you  are  in  the  streets,  and  you  will  avoid  many 
accidents. 

Fire  is  a  very  good  servant  but  a  dangerous  plaything. 
Playing  with  fire  is  one  of  the  useless  dangers  which  have 
caused  the  loss  of  many  lives.  Cotton  clothing  catches 
fire  very  easily,  and  playing  around  a  fire  of  burning 
leaves  is  therefore  dangerous.  Remember,  too,  that 
fires  spread  rapidly  if  they  get  a  chance.  Never,  there- 
fore, leave  a  camp  fire  in  the  woods  smoldering.  Never 
build  a  fire  in  or  around  barns,  for  hay  catches  easily  and 
burns  fiercely.  If  a  fire  starts  in  a  house  where  you  are, 
you  should  at  once  shut  up  the  room  where  it  is  and  notify 
the  fire  department.  If  it  is  a  small  fire,  you  can  put  it 
out  with  a  pail  of  water  or  smother  it  with  a  heavy  woolen 
rug. 

Firearms  are  especially  dangerous  playthings.  There 
is  a  sort  of  fascination  about  them  for  a  boy.  But 
every  little  while  we  read  in  the  papers  of  a  boy  shooting 
a  playmate  while  playing  with  a  gun  or  pistol.  Usually 
the  boy  had  no  idea  that  the  gun  was  loaded.  If  you  do 
play  with  firearms,  one  simple  rule  should  be  absolutely 
followed.  Never  point  a  gun  or  a  pistol  toward  another 
person,  even  if  you  are  sure  that  it  is  not  loaded. 
Another  good  rule  is  always  to  handle  a  gun  or  pistol  as 
if  it  were  loaded ;  if  you  do  this,  you  will  never  have  an 
accident  by  mistake. 

Electric  wires  cause  many  accidents  which  are  mostly 
avoidable.  Remember  that  a  "  live  wire "  is  deadly, 
and  that  any  wire  hanging  from  an  electric  pole  should 
be  regarded  as  a  live  wire.  Don't  touch  it  even  with  the 
shoe.  Don't  fly  kites  near  trolley  wires.  In  dry  weather 


370  PHYSIOLOGY   AND    HEALTH 

this  may  not  be  dangerous.  But  in  wet  or  damp  weather 
a  kite  string  touching  a  trolley  wire  has  been  known  to 
carry  the  current  of  electricity  and  to  kill  the  boy  holding 
it. 

Another  class  of  needless  accidents  comes  from  teasing 
dogs.  Once  in  a  while  there  may  be  dogs  that  will 
bite  without  any  especial  reason.  But  as  a  rule  dogs 
will  not  bite  unless  teased.  They  like  to  be  played  with, 
but  will  resent  being  abused.  If  you  get  bitten,  it  is  likely 
to  be  your  own  fault.  It  is  a  good  rule  to  let  strange  dogs 
alone.  Playing  with  them  is  a  dangerous  amusement. 

A  FEW   GOOD   HEALTH   RULES 

The  whole  purpose  of  studying  physiology  is  to  teach  us 
to  keep  well  and  strong.  Health  is  a  treasure  so  precious 
that  no  price  is  too  dear  to  pay  for  it.  But  to  keep  well 
involves  many  things.  You  do  not  need  to  remember 
everything  you  have  learned  about  the  structure  of  the 
body  in  order  to  be  able  to  follow  good  habits  of  living. 
The  most  important  rules  for  keeping  well  that  we  have 
been  studying  in  previous  chapters  are  as  follows : 

Keep  the  teeth  clean  by  thorough  and  frequent  brush- 
ing and  by  the  use  of  a  soft  toothpick  or  dental  floss. 

Chew  your  food  thoroughly,  giving  attention  to  its 
taste,  but  with  no  thought  of  swallowing  until  it  swallows 
itself.  Avoid  the  "  quick  lunch." 

Stop  eating  when  you  have  satisfied  the  appetite  and 
do  not  add  a  lot  of  sweet  food  because  it  tastes  good.  If 
you  are  going  to  eat  a  dessert,  save  room  for  it. 

Have  a  variety  in  what  you  eat.  The  body  does  not 
like  too  much  sameness  in  its  foods. 


HEALTH  HABITS  AND  OCCUPATIONS  371 

Be  careful  not  to  eat  too  much  food  that  is  rich  in 
protein.  Meat  twice  a  day  is  better  than  three  times  a 
day ;  and  once  a  day  is  still  better.  If  you  eat  meat  at 
other  meals  than  dinner,  eat  very  little. 

Keep  your  hands  clean  by  frequent  washing.  Dirt 
under  the  finger  nails  not  only  looks  slovenly  but  is  liable 
to  contain  dangerous  germs. 

Keep  everything  out  of  your  mouth  except  your  food 
and  drink.  You  do  not  know  what  dangerous  germs 
may  be  on  your  fingers,  or  by  whom  the  money  in  your 
pocket  may  have  been  handled  last. 

Drink  only  pure  water  and  avoid  the  common  drinking 
cup. 

Exercise  all  of  your  muscles  and  your  mind  every  day. 
Find  some  kind  of  exercise  that  you  enjoy,  for  you  will 
get  the  most  benefit  from  that  kind. of  action.  Make  a 
pleasure  of  your  tasks. 

Use  your  muscles  sufficiently  to  stimulate  the  action 
of  the  heart  and  lungs. 

Be  sure  that  your  exercise  brings  into  action  not  only 
your  arms  and  legs  but  the  muscles  of  your  back  and 
abdomen.  Let  the  exercise  be  varied.  A  horse  that 
travels  over  a  level  road  tires  more  quickly  than  one  going 
up  hill  and  down. 

Don't  continue  exercise  long  enough  to  become  tired. 
Fatigue  poisons  that  are  developed  by  over-exertion  are 
harmful.  You  get  the  best  rest  when  lying  down  or  sleep- 
ing. 

Keep  out  of  doors  as  much  as  possible,  in  winter  as 
well  as  in  summer. 

Breathe  through  the  nose  and  not  through  the  mouth. 


372  PHYSIOLOGY   AND   HEALTH 

See  that  the  air  in  the  rooms  you  occupy  is  moving. 
Coolness,  dryness,  and  motion  of  the  air  are  more  valuable 
than  heat.  Too  much  heat  rather  than  too  little  is  the 
usual  cause  of  colds. 

Wear  only  just  enough  clothing  to  keep  you  warm. 
To  feel  cold  occasionally  is  stimulating  rather  than  weak- 
ening. Porous  clothing  is  far  better  than  finely  woven 
clothing. 

A  frequent  bath  is  needed  for  skin  gymnastics.  A 
cold  bath  in  the  morning,  or  a  warm  one  followed  by  a 
cold  one  with  rubbing,  will  soon  enable  you  to  laugh  at 
"  colds." 

Never  bathe  in  polluted  water. 

See  that  all  cuts  and  bruises  of  the  skin  are  immediately 
washed  in  clean  water  and  that  tincture  of  iodine  is  applied 
as  soon  as  possible. . 

Gain  control  over  your  will  power  by  doing  something 
every  day  that  you  do  not  enjoy  doing  and  which  there- 
fore requires  determination.  'A  will  power  that  you  can 
master  is  one  of  your  most  valuable  assets,  but  a  will 
that  masters  you  is  sure  to  be  a  lifelong  handicap.  >  _ 

Cultivate  the  habit  of  thinking  of  pleasant  things  rather 
than  of  unpleasant  things,  and  believe  that  good  rather 
than  evil  is  going  to  happen. 

Spend  at  least  eight  hours  out  of  every  twenty-four  in 
bed  and  if  possible  asleep. 

Do  not  dull  the  edge  of  your  mind  by  drugs,  either 
tobacco,  alcohol,  or  any  other  narcotic. 

Always  believe  you  are  going  to  keep  well. 

Remember  that  the  secret  of  success  is  work;  the 
secret  of  failure  is  love  of  ease. 


HEALTH   HABITS  AND  OCCUPATIONS  373 

QUESTIONS 

1.  Mention  some  dangerous  occupations  not  given  in  this  chapter. 
Mention  some  that  are  safe. 

2.  Describe  some  " safety  first"  precautions  that  you  have  seen. 

3.  How  much  time  did  you  spend  out  of  doors  yesterday?     How 
much  time  were  you  occupied  in  active  exercise  ? 

4.  If  you  had  your  choice,  how  would  you  spend  your  vacation? 
Of  the  kinds  of  vacation  plans  which  are  open  to  you,  which  do  you 
prefer  ? 

5.  Why  are  vacation  schools  more  valuable  in  the  city  than  in  the 
country  ? 

6.  Why  is  a  cheap  moving  picture  theater  a  dangerous  place?    Give 
several  reasons. 

7.  Why  should  you  try  to  avoid  crowds? 

8.  Mention  some  kinds  of  accidents  that  come  from  carelessness, 
not  spoken  of  in  this  chanter. 


CHAPTER   III 

PUBLIC  HEALTH  AND   HEALTH   OFFICIALS 
The  Growth  of  Sanitary  Science 

THE  improvement  in  public  health  has  been  largely 
the  result  of  the  study  of  germ  diseases.  It  has  been 
only  a  few  years,  less  than  fifty,  since  the  important  facts 
concerning  bacteria  have  been  known.  In  earlier  years 
people  were  quite  unable  to  check  epidemics,  since  they 
did  not  know  what  caused  them.  So  many  were  the 
deaths  caused  by  them  that  for  many  centuries  there  was 
practically  no  increase  in  the  population  of  Europe,  as 
many  people  dying  each  year  as  were  born.  In  the  cities 
the  dangers  were  particularly  great,  more  people  dying 
each  year  than  were  born.  Cities  continued  to  exist 
only  because  people  from  the  country  kept  coming  to 
the  cities  to  take  the  places  of  those  who  died. 

To-day  all  this  is  changed.  We  have  learned  to  fight 
the  tiny  foes  that  caused  such  havoc.  We  have  learned 
where  they  live,  how  they  travel  from  person  to  person, 
and  how  they  may  be  rendered  harmless  or  killed.  As 
fast  as  these  facts  are  learned,  those  who  are  inter- 
ested in  improving  health  have  devised  regulations  de- 
signed to  control  the  causes  of  disease  and  to  check  the 
spread  of  the  ravaging  epidemics.  There  has  thus  been 
created  what  is  called  Sanitary  Science,  a  study  that  has 

374 


PUBLIC   HEALTH   AND  HEALTH   OFFICIALS        375 

come  into  existence  in  the  last  fifty  years  and  has  already 
produced  wonderful  results. 

The  difference  between  the  early  days  and  to-day  may 
be  shown  by  a  very  interesting  contrast.  In  1570  A.D. 
the  black  plague  appeared  in  Moscow,  and  200,000  people 
died  of  it.  In  1665  the  same  disease  appeared  in  London. 
More  than  half  the  people  ran  away,  but  of  those  that 
remained  69,000  died.  Stories  of  those  days  show  a  ter- 
rible condition  of  things.  So  rapidly  did  the  people  die 
that  no  attempt  was  made  to  hold  funerals.  Every 
day  carts  would  drive  through  the  streets.  The  drivers 
would  call  out,  "  Bring  out  your  dead,"  and  the  bodies 
of  those  who  had  died  during  the  day  would  be  brought 
out  and  carted  away.  What  a  pleasant  contrast  does  our 
twentieth  century  show  !  Within  recent  years  this  same 
terrible  disease  has  more  than  once  appeared  in  our 
country ;  but  in  each  case  prompt  measures  have  stamped 
it  out  before  it  has  been  able  to  do  much  harm.  People 
did  not  know  in  1665  what  we  know  now  —  that  rats  are 
the  means  of  distributing  the  disease.  Now,  at  the  first 
suspicion  of  the  plague,  the  people  begin  to  kill  the  rats. 
The  city  affected  has  been  really  benefited,  since  the  mere 
hint  of  the  plague  has  meant  a  thorough  cleaning  up. 

Where  people  are  crowded  together  by  hundreds  of 
thousands  or  millions,  many  problems  arise  —  of  food  sup- 
ply, water  supply,  waste  materials,  etc.  —  which  do  not 
occur  in  small  villages.  Epidemics  are  much  more 
serious  in  the  cities,  since  germs  are  more  easily  carried 
from  person  to  person.  In  past  centuries  these  greater 
dangers  have  made  life  in  the  city  noticeably  less  health- 
ful than  life  in  the  country. 


376  PHYSIOLOGY   AND    HEALTH 

Sanitary  science  has  developed  rapidly  in  the  cities, 
and  comparatively  little  in  the  country.  The  small 
community  has  fewer  difficulties  to  contend  with,  it 
also  has  less  money  for  investigation,  and  less  infor- 
mation. As  a  result  less  attention  has  been  given  to 
health  problems.  The  health  of  the  city  has  been  steadily 
advancing,  while  that  of  the  country  has  shown  fewer 
signs  of  improvement.  At  the  present  time  the  health 
of  the  city  has  come  to  be  nearly  as  good  as  that  of  the 
country.  The  population  of  the  cities  is  increasing. 
This  means  that  people  live  longer,  that  not  so  many 
children  die,  and  that  one's  chance  of  living  a  normal 
life  is  constantly  increasing.  Fifty  years  ago  a  new- 
born babe  had  on  an  average  about  twenty-five  years 
to  live.  Many  of  course  lived  to  middle  life  or  to  old 
age,  but  many  died  much  younger,  so  that  the  aver- 
age length  of  life  was  about  twenty-five  years.  At  the 
present  time  the  average  is  nearer  forty  years,  and  this 
happy  change  has  been  brought  about  by  sanitary  science. 

How  Public  Officials  Guard  Health 

Many  of  the  conditions  which  control  health  are  within 
the  reach  of  each  individual.  We  can  regulate  our  own 
food  and  drink,  the  amount  of  food  that  we  eat,  the  times 
of  eating.  We  can  arrange  our  lives  so  as  to  get  plenty 
of  exercise  and  air,  we  can  treat  our  cuts  or  bruises  and 
broken  bones  so  that  we  do  not  seriously  suffer  from  them. 
But  there  are  other  problems  that  are  not  within  the  reach 
of  the  individual  to  control.  If  we  live  in  a  city,  we  must 
use  the  public  water  supply,  we  must  buy  the  milk  that  is 
offered,  and  purchase  food  in  the  public  market.  When 


PUBLIC   HEALTH  AND   HEALTH   OFFICIALS        377 

epidemics  break  out  in  the  community,  individuals  are 
practically  helpless  in  most  cases  to  fight  against  them. 
We  cannot  avoid  meeting  people,  and  if  some  of  them  have 
contagious  diseases  we  cannot  avoid  the  contagion. 
There  are  thus  some  public  problems  which  have  to  be 
handled  for  the  people  as  a  whole. 

To  protect  the  public  from  unseen  dangers  Boards  of 
Health  have  been  very  generally  established  by  law. 
Each  state  has  a  State  Board  of  Health,  composed  of  a 
number  of  men  chosen  especially,  for  their  knowledge  and 
public  spirit.  It  is  the  duty  of  such  a  board  to  make  reg- 
ulations that  concern  the  whole  state,  and  to  give  advice  to 
the  cities  and  towns  on  matters  relating  to  public  health. 

There  are  also  city  and  town  Boards  of  Health  or  special 
Health  Officers,  whose  duty  it  is  to  see  that  proper  regu- 
lations for  the  protection  of  the  public  are  made  and 
carried  out.  Besides  these  there  are  Water  Boards,  whose 
duty  it  is  to  provide  and  to  guard  the  water  supply ; 
M ilk  Inspectors  to  watch  the  milk ;  Food  Inspectors  to 
see  that  only  proper  food  is  offered  for  sale.  Sometimes 
there  are  Sewage  Commissioners  to  see  that  sewage  is 
properly  disposed  of,  and  Tenement  Inspectors  whose 
duty  it  is  to  see  that  the  houses  in  which  people  live  are 
in  a  healthful  condition. 

Each  one  of  these  boards  has  its  important  work  to 
do ;  for  the  health  of  the  community  depends  largely 
upon  its  water  supply,  its  food  and  milk  supply,  the  pure 
air  in  its  houses,  and  the  disposal  of  its  sewage.  Every- 
body should  remember  that  these  various  officers  are 
working  for  the  common  good,  and  we  should  all  be  will- 
ing to  follow  their  directions  carefully. 


378  PHYSIOLOGY   AND    HEALTH 

These  officials  are  concerned  with  problems  of  public 
health  which  the  individual  cannot  handle.  Indigestion 
may  cause  much  misery,  but  it  is  not  a  problem  for  health 
officials.  It  is  their  duty,  however,  to  guard  the  purity 
of  the  foods  sold  in  the  markets,  since  the  individual  has  to 
buy  what  is  offered  in  the  markets.  The  individual  may 
go  from  one  to  another  and  select  the  best  food  he  can 
find,  but  alone  he  cannot  do  anything  to  improve  the 
quality  of  the  food  offered  for  sale. 

Where  the  Officials  Do  Their  Work.  —  Some  of  the 
problems  that  public  officials  have  to  attend  to  are 
confined  to  the  community  in  which  they  live.  The 
milk  inspector,  water  and  sewage  commissioner,  street 
commissioner,  tenement  inspector,  local  health  officer,  do 
their  work  in  and  specially  for  the  locality  where  they 
live. 

But  there  are  other  problems  that  extend  beyond  the 
city  limits ;  hence  various  state  departments  are  formed 
for  handling  them,  -r-  state  boards  of  health,  food  com- 
missioners, factory  inspectors,  cattle  commissioners,  and 
sewage  commissioners  which  have  duties  and  power  that 
differ  in  different  states  ;  but  in  general  they  are  supposed 
to  consider  problems  affecting  the  whole  state,  and  some- 
times to  appoint  and  to  advise  the  local  officials  of  the 
towns  and  cities. 

There  are  some  public  problems  which  extend  be- 
yond the  boundary  of  the  states.  A  large  part  of  the 
meat  sold  in  our  markets  comes  from  a  few  western 
states  and  is  slaughtered  in  the  great  stockyards  of  a 
few  cities.  Oysters  are  shipped  from  the  seashore  all 
over  the  country.  Foods  are  constantly  sent  by  rail- 


PUBLIC   HEALTH   AND   HEALTH   OFFICIALS        379 

roads  from  state  to  state.  Rivers  flow  from  one  state 
to  another,  and  the  sewage  which  one  state  pours  into 
the  stream  may  injure  a  neighboring  state.  Epidemics, 
too,  are  carried  from  state  to  state  by  travelers  or  by 
animals,  so  that  the  whole  country  may  be  put  in  danger 
from  a  contagious  disease  that  enters  any  port.  Such  wide 
problems  cannot  be  handled  by  local  or  by  state  officials. 
National  officers  are  therefore  appointed  whose  duty  it  is 
to  study  and  handle  nation-wide  problems  and  also  to  aid 
state  or  local  officials  in  solving  problems  that  may  be  of 
interest  to  the  public  generally. 

Working  in  harmony,  these  various  kinds  of  public 
guards  are  continually  trying  to  bring  about  healthful 
conditions  in  our  foods,  homes,  and  communities  gener- 
ally. Without  these  public  guardians  of  health  and 
supplies,  our  large  cities  would  be  far  more  liable  to  in- 
fection, and  disease  epidemics  would  be  much  more 
numerous  and  serious  than  they  are.  It  is  the  combined 
action  of  such  public  officials  that  has  so  noticeably  in- 
creased the  average  length  of  life  in  modern  times.  Fifty 
years  ago  most  of  these  offices  did  not  exist. 

The  Duty  of  the  Individual.  —  While  public  officials 
have  the  duty  of  controlling  public  health,  it  is  impos- 
sible for  them  to  be  successful  unless  the  people  of  the 
community  help  them.  It  is  not  only  necessary  that 
rules  be  made,  but  also  that  the  people  shall  understand 
and  follow  them.  Each  person,  young  and  old,  has  his 
part  to  play  in  the  control  of  public  health.  Sometimes 
the  regulations  of  the  public  officials  are  troublesome,  and 
to  the  ignorant  they  may  seem  unnecessary.  Occasionally 
they  may  seem  to  interfere  with  the  individual's  rights, 


380  PHYSIOLOGY   AND   HEALTH 

and  they  are  frequently  rather  inconvenient  to  follow. 
When  the  health  officer  sends  children  home  from  school, 
the  parents  are  sometimes  inclined  to  object.  When  the 
regulation  against  spitting  in  public  places  is  put  in  force, 
many  thoughtless,  ignorant  people  think  it  ridiculous 
and  take  delight  in  breaking  the  rule.  It  is  very  con- 
venient to  throw  waste  material  into*  the  street,  and  it  is 
much  more  trouble  to  put  this  refuse  into  receptacles 
specially  designed  for  the  purpose.  But  all  of  these  du- 
ties represent  part  of  the  price  that  we  must  pay  for 
health,  and  the  fifteen  or  twenty  extra  years  of  life  that 
sanitation  has  given  to  us  are  certainly  worth  paying  for, 
even  at  the  expense  of  a  little  inconvenience.  There  are 
always  good  reasons  for  the  public  health  regulations,  even 
though  we  may  not  at  all  times  understand  why  they  are 
necessary.  It  is  the  duty  of  the  good  citizen  to  follow 
them.  This  applies  to  the  boys  and  girls  just  as  much  as 
to  grown  people. 

QUESTIONS 

1.  What  is  an  epidemic? 

2.  Why  are  dangers  from  contagious  diseases  greater  in  the  city 
than  in  the  country? 

3.  Give  some  reasons  why  cities  are  to-day  more  healthful  than  in 
former  years. 

4.  What  is  the  need  for  Public  Health  Officers?     Has  your  com- 
munity all  the  public  officials  mentioned  in  this  chapter? 

5.  Why  have  not  people  a  right  to  live  as  they  choose  ? 

6.  Do  you  think  that  fifty  cents  a  year  is  too  much  for  each  person 
to  pay  each  year  for  public  health?     Can  you  find  out  how  much 
your  community  pays  per  person  for  public  health  work? 


CHAPTER   IV 
HOW  OUR  FOOD  AND  DRINK  ARE  GUARDED 

THE  problems  that  relate  to  public  health  may  be 
classified  in  three  groups :  (1)  The  guarding  of  public 
supplies.  (2)  The  disposal  of  waste.  (3)  The  preven- 
tion of  epidemics. 

The  Water  Supply  in  the  Country.  —  A  good  water 
supply  is  one  of  the  first  things  to  think  of  in  locating 
a  home.  In  the  country,  each  home  as  a  rule  must 
provide  its  own  water.  It  is  common  to  use  the  water 
from  a  spring,  a  well,  a  cistern,  or  sometimes  from  a 
stream;  but  in  each  case  the  individual  must  guard  his 
own  supply.  A  clear,  running  spring  is  the  safest  kind  of 
water.  Cisterns  which  catch  rain  water  are  also  usually 
safe  if  they  are  properly  guarded.  Water  from  wells  is 
generally  unsafe  for  a  home,  although  if  wells  are  properly 
located,  the  water  is  not  dangerous.  (See  Chapter  VI, 
Section  I.)  The  water  from  a  well  may  be  cold  and 
look  perfectly  clean  and  clear,  and  yet  may  be  decidedly 
dangerous  to  drink.  You  cannot  determine  whether 
water  is  safe  merely  by  looking  at  it ;  it  must  be  analyzed 
in  a  laboratory  to  determine  its  safety.  Deep  wells  are 
more  likely  to  be  safe  than  shallow  wells,  and  the  water 
from  an  artesian  well,  that  comes  from  many  feet  below 
the  surface,  is  almost  always  reliable,  if  it  is  drawn  in  clean 
pipes  and  is  not  contaminated  at  the  surface.  Water 

381 


382  PHYSIOLOGY   AND   HEALTH 

from  running  streams  is  most  open  to  suspicion,  especially 
if  there  are  people  living  on  the  banks  of  the  stream,  above 
the  point  where  the  water  supply  is  taken. 

The  Water  Supply  in  Cities.  —  In  the  city  the  people 
must  have  a  common  water  supply.  Hence  Water 
Commissioners  or  Water  Boards  are  appointed  to  see  that 
a  sufficient  supply  of  water  is  available  and  that  it  is  pure 
and  safe.  In  a  large  city  water  from  wells  is  never  safe 
to  use  because  the  soil  of  such  a  city  is  almost  sure  to  be 
soaked  with  filth  from  the  houses.  For  this  reason, 
the  use  of  well  water  in  large  cities  has  been  practically 


FIG.  102.  —  ONE  OF  THE  BEST  SOURCES  FOB  A  WATER  SUPPLY. 

abandoned,  and  as  this  has  been  done,  the  health  has 
improved.  Moreover,  a  large  city  needs  so  much  water 
that  wells  could  not  furnish  a  sufficient  supply.  One 
of  the  difficult  problems  for  a  big  city  is  to  get  a  sufficient 
supply  of  water  for  its  needs. 

The  best  sources  for  a  large  supply  are  lakes  and 
reservoirs,  in  which  the  water  has  a  chance  to  stand 
for  a  long  time ;  for  in  the  course  of  a  couple  of  months 
it  becomes  purified,  even  though  it  might  have  been 
polluted  originally.  For  the  purpose  of  keeping  such 
water  pure  and  safe,  water  commissioners  fence  in  the 
reservoirs  to  keep  the  public  away  from  them.  Many 


HOW  OUR  FOOD   AND   DRINK  ARE   GUARDED     383 

people  are  either  careless  or  thoughtless,  and  to  allow 
the  public  generally  to  frequent  these  reservoirs  would 
be  likely  to  result  in  contamination.  Sometimes  the 
water  board,  in  order  to  get  a  sufficient  supply,  is  forced 
to  depend  upon  water  from  streams  or  rivers.  Nearly 
all  rivers  have  small  or  large  communities  on  their  banks, 
the  sewage  from  which  is  almost  sure  to  drain  into  the 
river.  If  therefore  a  city  is  obliged  to  depend  upon  water 
from  such  a  source,  it  must  be  purified  before  it  can  be 
safely  used.  Hundreds  and  even  thousands  of  people 
have  suffered  from  typhoid  fever  because  the  water 
supply  of  the  community  has  been  taken  from  some 
polluted  stream. 

In  such  cases  the  water  board  endeavors  to  find  means 
to  purify  the  water,  so  as  to  make  it  wholesome  before 
allowing  it  to  be  distributed  over  the  city.  One  method 
of  purifying  water  is  by  filtering.  We  should  all  under- 
stand, however,  that  the  small  filters  that  we  sometimes 
see  attached  to  the  faucets  in  our  homes  are  of  no  value 
in  removing  danger  and  do  not  render  the  water  fit  to 
drink  if  it  was  previously  contaminated.  The  disease 
germs  are  so  small  that  they  can  readily  pass  through 
such  filters,  and  while  these  filters  may  make  the  water 
look  cleaner,  they  do  not  make  it  any  the  less  dangerous. 
There  are,  however,  methods,  by  the  use  of  great  beds 
of  sand,  of  filtering  water  in  such  a  way  as  to  remove  the 
dangerous  bacteria  at  the  same  time  that  the  dirt  is  re- 
moved. Such  large  filters  are  rather  expensive,  but  they 
are  in  use  in  many  places,  and  insure  to  the  community  a 
supply  of  pure  drinking  water. 

Sometimes  other  methods  are  used.     A  very  minute 


384  PHYSIOLOGY   AND    HEALTH 

quantity  of  chloride  of  lime,  perhaps  not  much  more  than 
one  part  to  a  million  parts  of  water,  is  added  to  the  water 
as  it  flows  into  the  city  pipes.  This  is  sufficient  to  de- 
stroy the  disease  germs  almost  immediately,  without 
injuring  the  water.  Occasionally  chlorine  gas  is  used 
instead  of  chloride  of  lime,  minute  quantities  of  gas 
being  discharged  into  the  water  by  a  specially  designed 
apparatus.  These  two  methods  are  coming  to  be  more 
and  more  widely  used  every  year. 

In  times  of  special  danger  the  health  officials  are  likely 
to  advise  the  boiling  of  all  drinking  water.  You  may  be 
sure  that  when  such  advice  is  given  publicly  there  is 
emphatic  reason  for  it,  and  especial  reason  for  believing 
that  the  water  is  unsafe  and  is  causing  illness.  Such 
advice  should  be  invariably  followed  by  every  one. 

Every  one  who  uses  the  public  water  ought  to  remem- 
ber that  the  supply  is  usually  limited,  and  that  by  wast- 
ing it  you  are  not  doing  your  part  as  a  good  citizen. 
Some  people  say  that  water  ought  to  be  free,  since  it 
comes  from  the  rain  for  the  benefit  of  all.  It  would  be 
free  to  you  if  you  could  get  your  own  water  supply  from 
the  rain.  But  it  cannot  be  free  if  it  must  be  piped  from 
distant  streams  or  distant  reservoirs  into  your  homes,  so 
that  you  can  have  it  three  hundred  and  sixty-five  days 
in  the  year.  Do  not  waste  it. 

The  Milk  Supply.  —  Do  you  know  where  the  milk 
that  you  used  on  your  cereal  for  breakfast  came  from? 
If  you  live  in  a  small  community,  you  may  know  that  it 
came  from  a  neighbor's  dairy  or  perhaps  from  your  own 
cows.  But  even  if  it  came  from  a  neighbor's  dairy,  you 
are  not  sure  that  it  is  clean,  for  dirt  may  get  into  the  milk 


HOW  OUR  FOOD  AND   DRINK  ARE   GUARDED     385 


at  any  time,  and  thus  though  it  may  reach  you  fresh  it 
may  not  be  necessarily  clean.  Dirty  milk  means  sick- 
ness, especially  to  babies.  If  you  live  in  the  city,  you 
probably  have  no  idea  where  the  milk  you  use  comes  from, 
beyond  the  fact  that  it  is  produced  somewhere  from  cows. 

The  difficulty  in  furnishing 
pure  milk  is  that  it  spoils 
so  quickly.  During  the  milk- 
ing, while  it  is  in  the  barn 
and  dairy,  a  great  many  bac- 
teria are  sure  to  get  into  it 
from  the  air,  and  these  bac- 
teria like  the  milk  as  well  as 
you  do.  They  begin  to  feed 
upon  it  at  once,  in  the  mean- 
time growing  very  rapidly  and 
multiplying  prodigiously.  By 

feeding  upon  the  milk  they  cause  it  to  sour,  and  some- 
times cause  other  even  more  undesirable  changes  in  it. 
As  a  result,  milk  cannot  be  kept  long  without  becoming 
unfit  to  drink. 

Our  cities  require  large  quantities  of  milk  every  day. 
A  city  like  New  York,  for  example,  requires  two  mil- 
lion quarts  of  milk  each  day,  and  to  provide  this  large 
quantity,  milk  must  be  carried  by  train  long  distances, 
often  hundreds  of  miles,  so  that  it  may  be  two  or  more 
days  old  by  the  time  it  is  delivered  at  the  homes  of  the 
people  that  are  to  use  it.  During  all  this  time  the  bac- 
teria that  are  in  the  milk  are  increasing  rapidly  and 
spoiling  it. 

Bacteria  spoil  milk  rapidly  if  the  temperature  is  high, 


FIG.    103.  —  MILKING    TIME    IN    A 
CLEAN  BARN. 


386 


PHYSIOLOGY   AND    HEALTH 


and  slowly  if  the  temperature  is  low.  Hence  refrigerator 
cars,  in  which  the  milk  can  be  kept  cold  during  its  journey, 
are  made  for  carrying  it  to  the  city.  Every  effort  is  made 
to  keep  the  milk  cold  until  it  is  delivered  to  the  consumer. 
After  the  milk  reaches  your  own  home  you  should 
remember  that  milk  will  spoil  quickly  by  the  growth  of 
bacteria  if  you  allow  it  to  become  warm.  In  many  cases 
when  milk  spoils  the  purchaser  blames  the  dealer  when 
it  is  in  fact  his  own  fault.  You  should  always  be  sure 


FIG.  104.  —  OUR  CITIES  REQUIRE  LARGE  QUANTITIES  OF  MILK. 

that  milk  is  placed  in  a  perfectly  clean,  covered  vessel, 
preferably  in  the  bottle  in  which  it  comes,  and  placed  at 
once  in  a  refrigerator.  But  in  all  cases  you  should  plan 
to  use  it  as  soon  as  possible.  If  you  have  no  ice  chest  in 
your  home,  buy  milk  in  the  smallest  possible  quantities 
from  a  reliable  store,  where  it  is  kept  on  ice,  and  then 
consume  it  immediately  after  you  have  brought  it  into 
your  own  home. 

In  a  city  each  person  is  quite  incapable  of  guarding  the 
milk  supply  that  he  receives,  but  must  buy  the  milk  as 
it  comes.  In  order  to  guard  the  supply,  therefore,  there 
are  appointed  dairy  and  milk  inspectors.  Some  of  these 


HOW  OUR  FOOD   AND   DRINK  ARE   GUARDED      387 

visit  the  dairies  from  which  the  milk  comes,  to  see  that 
the  cows  are  kept  clean  and  in  a  healthy  condition,  that 
the  milk  pails  are  kept  clean  and  sterile,  that  the  milk 
is  cooled  and  promptly  shipped,  and  that  in  every  place 
where  it  is  handled  before  it  reaches  the  city  it  is  handled 
in  a  proper  way.  Other  inspectors  look  after  the  milk 


FIG.  105.  —  A  CLEAN  Cow  AND  A  CLEAN  MILKER. 

when  it  reaches  the  city,  endeavoring  to  see  that  it  is 
properly  delivered  to  the  consumer,  that  no  water  is 
added  to  it,  and  that  no  cream  is  taken  from  it.  They 
also  try  to  see  that  the  milk  is  clean  when  it  reaches  the 
consumer,  and  that  it  is  delivered  in  clean  cans  and  clean 
bottles. 

But  even  with  all  these  precautions  we  cannot  always 
be  sure  that  the  milk  is  safe.     To  make  milk  absolutely 


388  PHYSIOLOGY   AND   HEALTH 

safe  it  must  be  pasteurized.  Pasteurization  does  not 
affect  the  taste  of  the  milk,  or  lower  its  value.  Exten- 
sive experiments  in  feeding  babies  on  pasteurized  and 
unpasteurized  milk  have  been  carried  on  in  our  large 
cities,  and  they  have  shown  that  babies  fed  upon  pas- 
teurized milk  thrive  better  than  those  fed  upon  raw  milk, 
Doctors  who  have  had  charge  of  these  experiments  be- 
come very  enthusiastic  over  the  value  of  pasteurized  milk, 
and,  while  there  has  been  a  prejudice  against  its  use,  it 
is  rapidly  disappearing.  Sometimes  the  pasteurizing  is 
done  by  the  dealer,  and  the  milk  may  be  sold  as  pasteur- 
ized milk.  Sometimes  the  pasteurizing  is  done  at  the 
home ;  it  can  be  done  in  any  one's  kitchen  with  a  little 
care.  Remember  that  the  milk  should  be  heated  to  a 
temperature  of  145°,  tested  by  a  thermometer,  kept  at 
that  temperature  for  about  half  an  hour,  and  then  cooled. 
When  possible,  buy  pasteurized  milk  in  order  to  avoid 
the  hidden  dangers  which  cannot  otherwise  be  avoided. 

Milk  is  one  of  the  best  and  also  one  of  the  cheapest  of 
foods.  Children  are  more  liable  to  take  diseases  from 
milk  than  adults,  partly,  perhaps,  because  they  drink  so 
much  more  of  it.  It  is  therefore  especially  desirable 
that  the  very  best  of  milk  should  be  used  for  children. 
On  the  other  hand,  grown  people  may  perhaps  not  need  to 
be  so  careful,  and  can  use  a  less  reliable  kind  of  milk  with- 
out danger.  Some  communities  have  therefore  adopted 
the  plan  of  grading  the  milk  sold  in  the  market,  so  that 
the  purchaser  may  know  what  kind  he  is  buying.  Under 
such  a  system  milk  is  usually  graded  according  to  its 
quality  as  A,  B,  or  C.  Grade  A  is  the  best  and  costs  the 
most,  but  is  safest  for  the  use  of  children.  Sometimes 


HOW   OUR  FOOD   AND   DRINK  ARE   GUARDED      389 

it  is  pasteurized,  and  sometimes  not,  although  when  not 
pasteurized  it  comes  from  especially  tested  cows.  Grade 
B  costs  less  than  Grade  A,  and  is  not  so  safe  or  so  re- 
liable ;  it  is  regarded  as  safe  for  adults,  though  some- 
times not  for  children.  Grade  C  is  the  cheapest.  It  is 
not  safe,  and  should  never  be  used  for  drinking  purposes, 
although  it  is  perfectly  safe  to  use  for  cooking,  when  heat 
destroys  the  germs  that  may  be  in  it.  The  best  grade  to 
buy  is  Grade  A,  since  it  is  least  likely  to  produce  sickness, 
and  thus  in  the  end  is  really  the  cheapest.  Even  at  the 
price  of  Grade  A  milk,  it  is  one  of  the  cheapest  and 
best  of  foods  for  people  of  all  ages. 

Guarding  the  Food  Supply.  —  When  you  sit  down  to 
dinner  to-day,  see  if  you  can  tell  where  the  things  you  eat 
came  from.  You  probably  will  find  that  while  you  know 
the  source  of  a  few  .of  them,  most  of  the  things  that  you 
eat  come  from  you  know  not  where.  They  have  been 
bought  at  the  market,  but  how  they  made  their  way  into 
the  market  you  have  no  idea.  A  very  large  amount  of 
food  must  be  brought  into  our  cities  each  day  to  feed  the 
people,  and  much  of  it  must  be  brought  from  long  dis- 
tances. Even  in  the  country  village  the  grocery  store 
contains  food  that  comes  from  long  distances,  sometimes 
half  way  around  the  world.  You  will  find  that  the  whole 
world  has  contributed  to  your  dinner.  Inasmuch  as  the 
food  comes  from  such  long  distances,  there  is  no  way  that 
you  can  be  sure  that  it  is  pure  and  produced  under  proper 
conditions. 

In  the  haste  to  be  rich  many  dishonest  dealers  are 
tempted  to  sell  impure  food.  Sometimes  the  foods  in  the 
markets  are  adulterated  with  worthless  materials.  Some- 


390  PHYSIOLOGY   AND   HEALTH 

times  the  flesh  of  diseased  animals  is  sold  in  the  market. 
Sometimes  preservatives,  which  are  chemical  poisons, 
and  likely  to  be  injurious,  are  put  into  the  food.  They 
are  put  into  meat  to  prevent  its  spoiling,  but  they  do  more 
or  less  injury  to  it.  But  against  all  of  these  things  we 
as  individuals  have  no  means  of  protecting  ourselves. 
We  have  to  depend  upon  public  officials  to  guard  the 
purity  of  the  food  supply.  Such  public  officials  are 
constantly  at  work  examining  the  food  in  our  markets, 
and  the  animals  that  are  slaughtered  in  slaughter  houses 
to  see  that  they  are  healthy,  and  inspecting  the  various 
packing  houses  to  see  whether  they  are  clean  and  whole- 
some, and  in  short,  endeavoring  in  every  way  to  see 
that  the  food  we  buy  is  wholesome  and  pure.  A  na- 
tional Pure  Food  law  has  been  passed  by  the  govern- 
ment at  Washington,  and  there  is  quite  an  army  of 
people  engaged  all  over  the  country  in  seeing  that  this 
law  is  enforced  and  that  only  good  food  comes  to  the 
market. 

Cheap  Grades  of  Food  Are  Poor  Food.  —  While  it  is 
true  that  cheap  grades  of  food  are  usually  poor  food,  this 
does  not  mean  that  low-priced  foods  are  always  poor 
foods.  Milk,  for  example,  is  a  better  food  than  lobster, 
but  even  Grade  A  milk  is  much  cheaper  to  buy.  Many 
foods  are  high  priced  simply  because  they  are  scarce  or 
because  they  have  some  special  flavor  or  are  "  out  of 
season,"  and  not  because  they  are  really  more  valuable. 
Some  excellent  foods  are  cheap  simply  because  they  are 
abundant.  But  as  a  rule  the  cheaper  grades  of  any 
special  kind  of  food  are  less  economical  to  buy  than  the 
better  grades.  They  are  more  likely  to  be  adulterated 


HOW   OUR  FOOD   AND   DRINK  ARE   GUARDED      391 


FIG.  106.  —  ONE  SHOULD  BUY  THE  BEST  GRADES 
OF  CANNED  GOODS. 


and  more  likely  to  contain  harmful  preservatives.  This 
is  particularly  true  of  canned  goods  and  of  various  kinds 
of  candy,  because  the  cheaper  grades  of  these  foods  con- 
tain less  valuable 
food  elements 
and  much  that  is 
worthless  and 
even  dangerous. 
Cheap  candies 
frequently  con- 
tain harmful 
coloring  matter, 
put  into  them  to  give  a  bright  color  and  to  make  them 
more  attractive.  The  cheap  canned  goods  contain  the 
poorest  product  of  the  canning  factory,  the  refuse  that 
remains  after  the  best  material  is  put  into  higher  priced 
goods.  It  is  poor  economy,  therefore,  to  buy  cheap 
grades  of  food.  This  does  not  always  apply  to  fresh 
meat,  for  the  cheaper  cuts  of  meat  are  often  as  nutritious 
as  the  more  expensive  ones,  round  steak  being  just  as 
valuable  as  the  more  expensive  porterhouse.  In  the  case 
of  canned  meats,  however,  the  rule  applies  usually  that 
cheap  foods  are  poor  foods. 


QUESTIONS 

1.  Why  is  water  from  streams  more  dangerous  than  that  from 
reservoirs  ? 

2.  What  is  the  most  dangerous  kind  of  water  contamination? 

3.  How  could  you  decide  whether  the  water  of  a  well  is  fit  to 
drink? 

4.  Why  have  cities  given  up  wells  as  a  source  of  water? 


392  PHYSIOLOGY   AND    HEALTH 

5.  Since  rain  is  free  to  all,  why  do  we  not  have  a  right  to  waste 
the  city  water? 

6.  Why  is  it  harder  to  get  good  milk  in  summer  than  in  winter? 

7.  Why  should  you  put  milk  immediately  in  an  ice  chest? 

8.  Why  do  people  pasteurize  milk? 

9.  Which  is  more  economical,  to  pay  an  extra  cent  a  quart  for 
Grade  A  milk,  or  to  have  the  baby  get  sick  from  drinking  Grade  B 
milk? 

10.   What  are  the  duties  of  the  food  inspector? 


CHAPTER  V 

HOW  THE  COMMUNITY  IS  KEPT   CLEAN  AND   WHOLE- 
SOME 

Fresh  Air.  —  It  would  seem  that  every  one  should  be 
wise  enough  to  want  as  much  air  as  possible  in  his  home. 
Strange  to  say,  however,  there  is  not  infrequently  an  im- 
pression among  the  ignorant  that  fresh  air,  especially  at 
night,  should  not  be  breathed.  Others  who  do  not 
exactly  think  that  fresh  air  is  unwholesome  do  not  real- 
ize the  need  of  it  and  are  perfectly  contented  to  live  in 
small  rooms  with  insufficient  air.  If  left  to  themselves, 
many  of  the  people  in  the  large  cities  would  shut  them- 
selves up  in  improperly  ventilated  rooms,  with  windows 
closed,  many  living  and  sleeping  in  one  room.  We  can- 
not wonder  that  among  them  contagious  diseases  spread 
rapidly.  It  is  almost  impossible  to  convince  such  people 
that  there  is  a  better  way  of  living,  so  it  becomes  neces- 
sary to  have  certain  officials  whose  duty  it  is  to  see  that 
the  conditions  of  living  in  the  crowded  tenement  districts 
are  improved.  Sometimes  laws  are  passed  regulating 
the  amount  of  air  and  light  that  tenements  must  have. 

Cleanliness  and  health  go  together.  In  dirty  houses 
and  filthy  sections  of  the  city  there  is  the  most  sickness, 
while  in  the  cleaner  sections  there  is  much  less.  People 
generally  resent  having  health  officials  interfere  with  the 
way  in  which  they  live,  and  yet,  because  these  unsanitary 

393 


394 


PHYSIOLOGY   AND   HEALTH 


houses  may  be  centers  of  contagion,  in  the  interest  of  the 
public  good,  such  interference  is  necessary. 

Every  good  citizen  should  do  his  part  toward  making  his 
community  a  "  spotless  town."  Certain  special  precau- 
tions in  the  home  should  be  heeded.  The  kitchen  should 
be  the  cleanest  place  in  the  house.  Dishes  should  be 
thoroughly  washed  after  each  meal  in  boiling  water.  Care 


FIG.  107.  —  BREEDING  PLACES  FOB  MOSQUITOES. 

should  be  taken  that  the  dishes  used  by  a  sick  person  should 
all  be  soaked  in  boiling  water  for  five  minutes  after  being 
used.  Only  a  boor  will  spit  on  floors  or  walls,  and  .no 
real  housekeeper  will  allow  any  form  of  filth  to  collect  in 
her  house.  If  the  rooms  are  swept  with  a  broom,  the 
dust  should  be  allowed  to  settle  and  then  the  furniture 
should  be  wiped  with  a  damp  cloth.  Remember  that 
carpets,  rugs,  and  drapery  curtains  catch  and  hold  dust, 
and  thus  make  it  difficult  to  keep  the  room  clean.  Hos- 
pitals, where  they  are  particularly  careful  never  to  allow 
dust  to  accumulate,  have  long  since  abandoned  carpets 
and  drapery  curtains. 


HOW  THE   COMMUNITY  IS  KEPT  CLEAN 


395 


There  is  little  use  in  keeping  the  house  clean  if  the 
cellar  and  the  yard  are  allowed  to  become  filthy.     If 
the  girls  have  their  duties  indoors,  the  boys  should  have 
theirs  in  the  yard,  and  both  should  be  responsible  for 
keeping  the  school  yard  clean.     Because  people  in  gen- 
eral do  not  see  them,  the  back  yard  and  the  cellar  are 
likely  to  be  neglected  and 
frequently     become     the 
breeding    places    of    flies 
and  mosquitoes  with  all 
their  dangers.     No  water 
should  be  allowed  to  stand 
in    barrels,    pails,    pools, 
ditches   or  in   empty  tin 
cans.     Even  empty  bot- 
tles  and    the    gutters    of 
houses  may  become  filled 
with  rain  water  and  prove 
prolific  breeding  places  for  mosquitoes.     Filth  and  an 
open  garbage  can  offer  just  what  the  flies  want  for  their 
breeding  places. 

Outside  of  the  home  and  the  yard  we  depend  upon 
public  officials  to  keep  the  streets  clean.  The  dirt  and 
filth  that  we  remove  from  our  cellars  and  back  yards  we 
carry  to  the  street,  confidently  expecting  the  public  carts 
to  carry  it  away.  In  our  large  cities  there  is  quite  an 
army  of  men  tirelessly  at  work  sweeping,  washing,  and 
gathering  up  refuse  of  all  kinds.  We  do  not  commonly 
appreciate  what  we  owe  to  these  street  cleaners.  But  if 
you  could  for  a  few  moments  look  at  the  streets  of  our 
cities  as  they  were  forty  years  ago,  you  would  realize  it. 


FIG.  108. — A  STREET  CLEANER. 


396  PHYSIOLOGY   AND   HEALTH 

The  streets  in  our  large  cities  were  filled  with  mud  and 
filth  several  inches  deep,  even  the  best  streets  showing  a 
condition  that  does  not  exist  now  in  the  worst  parts  of 
our  cities.  If  you  could  go  back  still  further,  for  a  century 
or  more,  you  would  find  that  no  attempt  was  made  to 
keep  the  streets  clean  and,  seeing  the  unspeakable  filth 
there,  you  would  not  wonder  that  epidemics  used  to  rage, 
and  that  people  died  faster  than  they  were  born.  To- 
day health  rules  forbid  spitting  on  sidewalks,  etc.,  because 
of  the  danger  to  the  public  from  the  distribution  of  dis- 
ease germs. 

Disposal  of  Wastes.  —  Every  community  large  or 
small  has  waste  material  to  dispose  of,  and  in  the  larger 
communities  this  requires  several  sets  of  public  officials. 
These  wastes  are  of  three  kinds.  (1)  Ashes  and  unburn- 
able  material.  (2)  Garbage.  (3)  Sewage.  The  first 
two  are  sometimes  disposed  of  together. 

Ashes  and  Unburnable  Wastes.  —  Since  ashes  can- 
not be  destroyed,  it  is  sometimes  considerable  trouble  to 
get  rid  of  them.  Sometimes  they  are  used  to  fill  up  de- 
pressions or  for  building  up  streets.  A  depression  in  the 
ground  may  for  a  time  become  a  "  public  dump  "  and 
then  after  being  filled  furnish  some  new  building  lots. 
Sometimes  such  material  is  taken  to  the  sea  and  dumped. 

Garbage.  —  This  is  in  general  the  waste  from  the 
kitchen,  from  the  market,  etc.,  together  with  such  miscel- 
laneous material  as  any  one  may  chance  to  put  into  the 
garbage  can.  People  used  to  throw  such  things  into  the 
street  and  allow  them  to  putrefy  there.  There  were  no 
general  public  methods  of  disposing  of  garbage,  and  the 
streets  were  commonly  vile  smelling,  and  vile  looking, 


HOW  THE   COMMUNITY  IS  KEPT   CLEAN          397 

a  breeding  place  for  disease  germs,  rats,  and  insects. 
To  keep  free  of  the  filth,  people  in  walking  the  streets 
sometimes  wore  shoes  with  high  wooden  heels. 

No  city  in  our  day  would  tolerate  such  conditions. 
Such  material  is  first  required  to  be  placed  in  special  cans, 
which  should  always  be  kept  closed,  both  for  looks  and 
for  health  (remember  the  millions  of  flies  breeding  in  a 


FIG.  109.  —  A  GARBAGE  COLLECTOR. 

garbage  can).  Then  at  frequent  intervals  the  city  gar- 
bage carts  go  through  the  streets  collecting  the  garbage 
and  carrying  it  away.  Sometimes  it  is  fed  to  pigs ;  a 
bad  plan,  since  pigs  fed  in  this  way  often  become  diseased. 
This  is  the  chief  source  of  Trichina  found  in  pork.  (See 
page  19.)  A  plan  almost  as  bad  is  that  of  dumping  the 
garbage  together  with  the  ashes  into  ravines  in  the  city 
for  the  purpose  of  filling  them.  Such  places  become 
unsightly,  loathsome,  bad-smelling  localities  and  are  in- 
fested with  rats.  Sometimes  the  garbage  is  placed  on 
boats  and  towed  out  to  sea,  where  it  is  dumped,  or  per- 
haps it  is  dumped  into  a  river  to  the  detriment  of  those 
living  on  the  river  banks  below.  The  best  plan  is  one 


398  PHYSIOLOGY   AND   HEALTH 

that  is  being  more  and  more  adopted  by  cities,  and  con- 
sists in  burning  the  garbage  in  great  furnaces  called  in- 
cinerators. This  disposes  of  the  material  at  once  and 
with  the  least  trouble,  and  is  found  to  be  really  one  of  the 
cheapest  methods. 


FIG.  110.  —  DUMPING   GARBAGE  INTO  A  GARBAGE  Scow  TO  BE  TAKEN 
OUT  TO  SEA. 

Sewage.  —  Sewage  is  the  name  given  to  the  wastes 
from  toilets,  from  sink  drains,  from  wash  basins,  from 
the  roofs  of  houses,  and  from  the  street  gutters,  which  are 
carried  through  pipes  and  drains  into  the  sewers.  Sewage 
is  absolutely  the  most  dangerous  form  of  waste  that  the 
public  health  officers  have  to  deal  with,  since  it  contains 
such  a  large  amount  of  matter  excreted  from  human 
beings.  In  most  cities  the  sewage  from  all  houses  flows 


HOW  THE   COMMUNITY   IS  KEPT  CLEAN 


399 


into  long  underground  passages,  or  sewers,  which  extend 
under  the  streets.  Sewers  are  one  of  the  modern  devices 
for  keeping  the  city  clean,  which  the  cities  of  earlier 
centuries  did  not  have. 

This  great  mass  of  foul  material  must  be  disposed  of  in 
some  way,  and  it  has  not  been  easy  to  determine  what  to 


FIG.  111. — DIAGRAM  TO  SHOW  THE  WAY  WASTE  Is  REMOVED  FROM  A  CITY  HOME. 

do  with  it.  It  contains  so  much  water  that  it  cannot  be 
burned.  In  some  countries  it  has  been  conducted  out- 
side the  cities  and  spread  over  the  land  as  fertilizer,  but 
this  has  not  been  wholly  successful  in  this  country. 
Where  a  city  is  near  a  river,  a  common  practice  is  to 
empty  the  sewage  into  the  river.  This  contaminates 
the  water  so  that  towns  located  on  its  banks  below  are 
endangered.  Severe  epidemics  of  typhoid  fever  have 
been  traced  to  this  method  of  disposing  of  sewage.  Many 


400  PHYSIOLOGY   AND   HEALTH 

rivers  that  a  few  years  ago  were  clear,  clean  water,  full  of 
fishes,  have  become  vile  and  filthy  from  this  practice. 
Other  cities  located  on  the  ocean  empty  their  sewage  into 
the  harbor.  But  this  method  is  equally  objectionable. 
It  renders  seashore  resorts  unpleasant  if  not  dangerous, 
and  it  destroys  valuable  oyster  beds.  As  the  cities  grow 
and  produce  more  and  more  sewage,  the  trouble  becomes 
greater,  until  other  methods  have  to  be  resorted  to. 

The  best  method  of  disposing  of  sewage  is  to  destroy 
it.  There  are  several  ways  of  doing  this,  some  of  which 
are  by  means  of  septic  tanks,  filter  beds,  contact  beds, 
and  sprinkling  filters.  It  will  be  interesting  for  you  to 
learn  what  method  is  adopted  in  your  community  and 
to  visit  the  sewage  plant  some  day.  No  public  service 
contributes  more  to  public  health  and  comfort  than  the 
efficient  disposal  of  the  sewage  wastes. 

In  the  country  the  disposal  of  sewage  is  a  wholly  dif- 
ferent problem,  since  there  are  no  sewers.  As  a  rule  each 
house  has  to  take  care  of  its  own  wastes.  Occasionally 
they  are  burned.  Frequently  a  considerable  part  of  them 
is  mixed  with  other  fertilizers  and  used  for  fertilizing  the 
soil.  Part  of  them,  especially  that  from  the  kitchen  sink, 
is  simply  allowed  to  soak  into  the  ground.  The  great 
danger  is  that  some  of  this  material  will  not  be  properly 
taken  care  of  and  will  be  allowed  to  accumulate  where  it 
will  pollute  the  water  of  the  well.  Any  one  who  lives  in 
an  isolated  house  in  the  country  should  ever  bear  in  mind 
that  all  such  material  is  extremely  dangerous  and  should 
never  be  thrown  or  allowed  to  collect  where  there  is  any 
possible  chance  of  its  getting  washed  into  the  well  with 
the  rains  or  of  soaking  into  the  well  through  the  soil. 


HOW  THE  COMMUNITY   IS  KEPT  CLEAN          401 

QUESTIONS 

1.  Why  should  we  have  screens  at  windows  and  doors  in  summer  ? 

2.  Why   are   tenement   inspectors   needed   in    cities?    Are   they 
needed  in  a  small  community?    Give  a  reason  for  your  answer. 

3.  What  dangers  exist  in  a  filthy  back  yard? 

4.  Why  should  the  garbage  can  be  kept  covered  ? 

5.  What  is  the  objection  to  allowing  sewage  to  empty  into  a  stream  ? 

6.  How  is  sewage  disposed  of  in  your  community? 

7.  Can  you  tell  what  is  done  with  the  garbage  in  your  community? 

8.  Find  out  if  you  can  in  what  parts  of  your  town  or  city  tuberculosis 
and  pneumonia  find  the  most  victims.     Explain  why. 

9.  How  can  a  person  living  in  the  country  best  dispose  of  wastes 
so  as  to  avoid  danger? 


CHAPTER   VI 
HOW  THE   SPREAD   OF  EPIDEMICS   IS   CHECKED 

What  the  Experience  of  Armies  Has  Taught  Us.  — 

One  of  the  greatest  achievements  of  public  health  officials 
has  been  to  reduce  the  ravages  of  epidemics  which  used 
to  destroy  so  many  human  lives.  Epidemics  are  always 
germ  diseases,  and  their  control  has  been  brought  about 
chiefly  by  discovering  the  nature  of  these  germs,  learning 
where  they  live  and  how  they  are  distributed.  Germs 
do  not  travel  from  person  to  person  by  any  power  of 
motion  of  their  own.  They  are  always  carried  by  people, 
animals,  or  by  some  moving  object.  By  finding  out  how 
they  are  carried  and  then  by  devising  some  method  of 
preventing  it,  epidemics  have  become  largely  controlled. 
In  the  middle  ages  certain  contagious  diseases  which 
killed  vast  numbers  of  people  were  called  the  "  scourge 
of  God."  These  "  plagues "  would  sometimes  break 
out  when  thousands  of  people  gathered  from  different 
parts  of  the  world  on  a  pilgrimage  or  for  the  Crusades. 
It  was  the  same  then  in  the  armies ;  a  "  scourge  "  would 
break  out,  men  began  to  die  by  thousands,  and  the 
only  measure  they  could  take  was  to  disband  the  army  — 
which  often  meant  that  the  soldiers,  going  to  their  homes, 
took  the  disease  back  with  them.  Modern  armies  know 
that  they  have  to  fight  germs  as  well  as  their  enemies, 

402 


HOW  THE  SPREAD  OF  EPIDEMICS  IS  CHECKED     403 

and  they  have  learned  to  fight  equally  well  in  both  kinds 
of  warfare. 

Army  Precautions  in  1902. --The  first  demonstration 
of  the  extent  to  which  an  army  may  be  protected  from  its 
germ  enemies  was  given  by  the  Japanese  in  their  war 
with  Russia  in  1902.  Four  years  before  that  date,  our 
country  had  been  at  war  with  Spain.  Most  of  the  facts 
about  disease  germs  were  known  at  the  time  of  our 
war,  but  we  had  not  learned  what  to  do  about  them. 
The  result  was  that  for  every  one  of  our  soldiers  killed  by 
bullets  four  died  of  disease.  The  Japanese  had  worked 
out  plans  for  using  the  knowledge  of  germs  as  disease 
makers.  They  sent  their  doctors  and  scientists  ahead 
of  the  army,  to  locate  the  healthy  places  for  camps,  to 
learn  whether  the  water  of  the  streams  and  wells  was 
fit  to  drink,  and  to  discover  and  remove  any  conditions 
that  might  make  the  soldiers  sick  when  they  came  to 
camp.  The  Japanese  soldiers  were  told  that  it  was  just 
as  much  a  matter  of  patriotism  for  them  to  keep  well,  as 
it  was  to  be  brave  in  battle.  They  obeyed  the  directions 
of  the  advance  guards  as  no  other  body  of  men  had  ever 
obeyed  such  directions.  The  result  was  most  remark- 
able. In  the  Japanese  army  only  one  man  died  of  dis- 
ease for  every  four  that  were  killed  by  the  enemy.  Pre^ 
ventable  disease  almost  disappeared  from  the  army. 

Army  Precautions  of  1914.  —  The  armies  fighting  in 
the  great  European  war  of  1914  took  these  and  many 
similar  precautions.  Sometimes  bath  trains  were  sent 
along  the  railroad  in  the  rear  of  the  army  so  that  the  sol- 
diers, particularly  those  who  were  fighting  in  the  trenches, 
might  have  water  and  facilities  for  bathing,  because 


404  PHYSIOLOGY   AND   HEALTH 

cleanliness  was  known  to  be  such  an  important  aid  in 
preventing  contagious  diseases.  During  the  first  year 
of  that  war,  in  which  millions  and  millions  of  men  were 
fighting,  only  one  serious  epidemic  is  known  to  have 
broken  out  in  the  armies.  That  was  an  epidemic  of  a 
serious  disease  called  typhus.  Our  own  country  sent  a 
band  of  scientists,  doctors,  and  nurses  to  the  land  where 
the  epidemic  was  raging,  to  teach  the  people  how  to  get 
rid  of  the  disease.  They  showed  them  that  it  is  distributed 
by  the  bites  of  lice  which  trouble  the  soldiers,  and  that 
it  could  be  stopped  if  the  soldiers  could  only  keep  them- 
selves and  their  clothes  clean.  You  can  see  then  why 
they  follow  armies  with  bath  trains. 

How  the  Spreading  of  Diseases  Is  Prevented 

To  check  the  ravages  of  a  germ  disease  the  first  thing 
is  to  find  out  how  it  is  spread.  When  a  person  is  ill 
with  such  a  disease  the  germs  become  very  abundant  in 
his  body,  but  if  the  disease  is  to  spread,  the  germs  must 
be  carried  to  some  well  person.  Sometimes,  as  in  grip, 
measles,  diphtheria,  tonsillitis,  mumps,  etc.,  the  germs  are 
in  the  mouth  or  nose  of  the  patient ;  sometimes,  as  in 
typhoid  fever,  in  his  intestines  or  bladder,  and  sometimes, 
as  in  smallpox,  on  his  skin.  If  he  coughs,  the  germs  may 
be  scattered  into  the  air  so  that  another  person  coming 
near  him  may  breathe  them  into  his  lungs.  Or  a  well 
person  may  get  them  by  handling  the  clothes,  toys,  books, 
knives,  or  other  articles  that  the  patient  may  have  handled. 
There  is  nothing  mysterious  about  it.  It  is  simply  a 
case  of  the  germs  being  carried  from  the  body  of  a  sick 
person  to  a  well  one.  To  prevent  this,  the  health  officers 


HOW  THE  SPREAD  OF  EPIDEMICS  IS  CHECKED     405 

isolate  contagious  patients  and  quarantine  their  homes. 
They  may  even  prevent  other  members  of  the  family 
from  going  about,  to  prevent  the  possibility  of  their 
carrying  the  germs  into  other  families.  Houses  are 
pasted  with  notices  informing  the  public  that  a  conta- 
gious disease  is  present. 

This  method  is  of  value  only  for  diseases  that  pass 
directly   from   person   to   person.     With   other   diseases 


FIG.  112.  —  SOME  WAYS  IN  WHICH  DISEASE  GERMS  ARE  SPREAD. 

different  methods  are  necessary.  With  each  kind  of 
germ  disease  the  health  officer  tries  to  find  out  the  proper 
method  of  checking  its  distribution.  If  malaria  is  abun- 
dant, he  tries  to  get  rid  of  mosquitoes.  If  yellow  fever 
appears,  he  destroys  the  breeding  places  of  mosquitoes 
and  puts  the  patients  under  mosquito  netting  to  pre- 
vent mosquitoes  from  biting  them,  and  preventing  the 
germs  from  being  carried  to  other  people.  If  typhoid 
breaks  out,  the  water,  the  milk,  and  the  flies  are  suspected, 
and  each  is  examined  to  see  which  is  at  fault.  If  there 
is  a  suspicion  of  plague,  the  health  officials  begin  at  once 
to  kill  rats.  If  diphtheria  appears,  they  hunt  for  diph- 
theria carriers  and  isolate  them  for  a  while.  If  small- 
pox shows  itself,  they  not  only  carefully  isolate  the 
patients,  but  try  to  see  that  well  people  are  vaccinated 
against  the  disease.  Thus  each  disease  has  its  own  defense. 


406 


PHYSIOLOGY   AND   HEALTH 


Then  certain  general  methods  are  adopted  to  protect 
people  at  large. 

One  important  step  that  has  been  taken  is  to  discourage 
or  forbid  the  public  use  of  certain  toilet  articles.  No  one 
would  think  of  using  another  person's  toothbrush,  but 

many  people  have 
no  hesitation  in  us- 
ing a  public  drink- 
ing cup  or  a  com- 
mon towel.  The 
public  drinking  cup 
has  long  been  con- 
demned by  Health 
officers  because  it 
was  found  that 
through  it  conta- 
gious diseases  may 
be  transmitted 
from  one  person  to 
another.  The  ac- 
tual discovery  of 
disease  germs  on 
such  cups  showed 
that  some  steps  for  the  protection  of  the  public  must  be 
taken.  So  drinking  fountains  were  devised,  with  little 
jets  of  water  which  one  could  take  directly  from  the  foun- 
tain without  the  use  of  any  water  container ;  individual 
paper  cups  were  also  made  in  such  inexpensive  form  that 
it  is  possible  to  provide  them  in  quantities,  allowing  each 
person  in  a  public  place  to  use  a  fresh  cup.  These  cups 
are  now  provided  generally  on  railway  trains  and  in  many 


FIG.  113.  —  A  DRINKING  FOUNTAIN. 


HOW  THE   SPREAD   OF  EPIDEMICS   IS   CHECKED      407 

buildings  where  numbers  of  people  congregate ;  schools 
also  furnish  them.  Since  there  are  so  many  disease  germs 
constantly  about,  and  since  such  germs  are  found  in  the 
mouths  of  even  well  people,  it  is  evidently  criminal  fool- 
ishness not  to  take  all  reasonable  precautions  to  prevent 
the  transmission  of  them  from  one  person  to  another. 

How  Germ  Diseases  are  Limited  by  Resistance.  — 
There  is  one  fortunate  fact  about  most  of  the  diseases 
produced  by  germs.  If  we  are  attacked  by  one  kind  of 
contagious  disease,  and  recover  from  it,  we  are  pro- 
tected from  another  attack  of  that  particular  disease, 
even  if  exposed  to  it.  People  do  not  commonly  have  two 
attacks  of  the  same  disease,  for  when  they  recover  from 
the  first  attack  they  develop  power  to  resist  a  second. 
This  resistance  is  called  immunity.  It  lasts  sometimes 
for  many  years  or  perhaps  for  life.  We  should  under- 
stand, however,  that  the  different  germ  diseases  are  not 
alike  in  this  respect,  some  of  them  giving  immunity  for 
long  and  others  for  short  periods.  Yellow  fever,  scarlet 
fever,  smallpox,  chicken  pox,  mumps,  typhoid,  and  whoop- 
ing cough  are  very  rarely  taken  twice ;  if  they  are, 
the  second  attack  will  be  years  after  the  first.  Immunity 
from  measles,  pneumonia,  or  malaria  is  not  so  sure. 
Against  grip  and  diphtheria,  it  is  even  less  certain,  for 
another  attack  may  come  about  immediately.  Against 
consumption,  colds,  blood  poisoning,  boils  and  abscesses, 
and  summer  complaint,  we  do  not  seem  to  gain  immunity 
at  all ;  we  may  be  troubled  by  these  illnesses  over  and 
over  again.  Even  doctors  are  unable  to  tell  just  how  long 
this  immunity  lasts  in  all  cases,  and  the  statements  just 
given  are  only  general.  But  they  will  show  which  diseases 


408  PHYSIOLOGY   AND   HEALTH 

we  should  guard  against  and  which  ones  we  need  not  be 
anxious  about  after  the  first  attack. 

Isolation  Period.  —  The  length  of  time  during  which 
it  is  necessary  to  isolate  a  patient  in  order  to  insure  others 
against  contagion  varies  also  with  the  different  diseases. 
It  is  of  the  utmost  importance  that  the  advice  of  a  physi- 
cian should  be  sought  and  scrupulously  followed  in  re- 
gard to  this  point,  no  matter  how  "  light  "  a  case  may  be. 
Even  after  a  person  feels  perfectly  well,  he  may  be  just 
as  dangerous  to  another  person  as  he  was  when  he  was 
sick.  Such  minor  ailments  as  boils,  abscesses,  and  in- 
fected sores  of  all  kinds  are  a  source  of  germs  as  long  as 
they  continue  to  discharge  pus.  All  discharges  from  such 
sores  should  be  carefully  burned. 

Treatment  of  Infected  Objects.  —  Much  has  already  been  said 
about  how  objects  handled  or  used  by  a  patient  suffering  with  a 
contagious  disease  become  contaminated  with  germs.  All  articles 
of  little  value,  like  bits  of  cloth,  toys,  and  food,  should  be  destroyed. 
Boiling  for  fifteen  minutes  is  quite  sufficient  to  destroy  the  germs 
of  the  common  contagious  diseases,  germs  that  are  likely  to  be 
left  on  clothing,  towels,  bedding,  handkerchiefs,  eating  utensils, 
etc.  Steam  will  do  the  same,  if  it  can  be  applied  to  objects  in 
closed  vessels ;  and  so,  too,  will  the  dry  heat  of  a  hot  oven. 

Objects  which  cannot  be  boiled  may  sometimes  be  soaked  or 
washed  in  a  disinfectant.  These  disinfectants  are  solutions  which 
contain  chemicals  that  kill  germs  quickly.  They  are  all  poison- 
ous, should  always  be  labeled  POISON,  handled  with  care,  and 
never  taken  into  the  mouth. 

The  value  of  a  disinfectant  does  not  depend  in  the  least  upon 
the  strength  of  the  odor  from  it.  In  the  use  of  all  disinfectants 
it  is  necessary  that  the  object  be  actually  wet  with  the  disinfectant. 
Pouring  a  little  on  the  floor  of  a  room,  or  allowing  it  to  stand  in 
an  open  vessel,  is  of  no  value  whatsoever,  even  though,  like  car- 


HOW  THE  SPREAD  OF  EPIDEMICS   IS  CHECKED     409 

bolic  acid,  it  has  a  strong  odor.     The  odor  has  no  power  of  de- 
stroying the  germs.     Five  disinfectants  are  in  common  use. 

Formalin.  —  Formalin  is  a  powerful  disinfectant ;  it  looks  like 
water,  but  any  article  soaked  in  a  two  to  four  per  cent  solution  of 
it  will  be  thoroughly  disinfected,  and  it  is  no  more  injurious  to 
fabrics  than  water.  Formalin  gives  off  a  gas  that  is  very  irritating 
to  the  eyes  if  it  stands  in  the  open  air.  This  gas  is  the  real  disin- 
fecting agent,  and  health  officers  frequently  use  it  to  disinfect  a 
room  that  has  been  occupied  by  a  patient  with  a  contagious  disease. 

Corrosive  Sublimate.  —  Corrosive  sublimate  is  intensely  poison- 
ous and  must  be  handled  with  extreme  care.  As  a  solution,  one 
part  corrosive  sublimate  to  2000-4000  parts  water,  it  may  be 
used  to  disinfect  wounds.  When  a  powerful  disinfectant  is  needed 
for  use  on  inanimate  objects,  use  one  part  of  it  dissolved  in  1000 
parts  of  water.  It  comes  in  tablets,  with  directions  for  dissolving 
in  water  so  as  to  give  the  desired  strength.  It  may  be  used  for 
washing  floors,  furniture,  or  walls  of  rooms,  or  for  disinfecting 
excreta,  which  should  be  allowed  to  soak  in  the  disinfectant  an 
hour.  It  must  not  be  used  on  metals,  since  it  injures  them. 

Chloride  of  Lime.  - —  Chloride  of  lime,  or  bleaching  powder,  is 
one  of  the  cheapest  and  best  disinfectants.  One  pound  dissolved 
in  eight  gallons  of  water  gives  the  desired  strength.  It  is  a  good 
substitute  for  the  more  powerful  and  dangerous  corrosive  sub- 
limate ;  it  is  used  in  the  same  way  and  for  the  same  length  of  time ; 
it  does  not  injure  metals. 

•Iodine.  —  One  of  the  best  materials  to  be  used  for  disinfecting 
wounds  appears  to  be  iodine.  Tincture  of  iodine  can  be  purchased 
at  any  drug  store  and  should  be  kept  on  hand  in  every  home. 
It  does  not  irritate  the  tissues  and  can  be  applied  to  the  raw  flesh ; 
it  quickly  disinfects  the  wound,  i.e.  kills  all  the  germs  that  may  be 
on  it.  Sometimes,  especially  when  the  skin  is  greasy,  one  part 
of  benzine  is  mixed  with  two  parts  of  iodine.  The  benzine  helps 
clean  the  wound,  the  iodine  does  the  disinfecting.  If  the  skin 
can  first  be  washed  with  soap  and  water  and  then  with  alcohol, 
the  tincture  of  iodine  should  be  used  without  the  benzine.  Iodine 
ointments,  which  consist  of  iodine  mixed  with  some  greasy  sub- 
stance, make  an  excellent  material  to  apply  to  a  wound. 


410  PHYSIOLOGY   AND   HEALTH 

Carbolic  Acid.  —  Carbolic  acid  is  an  excellent  but  expensive 
disinfectant.  It  must  not  be  used  full  strength,  for  this  would 
burn  the  skin  badly.  One  part  of  the  acid  in  twenty  of  water 
is  best  for  most  purposes.  A  two  to  five  per  cent  solution  can  be 
used  upon  the  flesh  to  disinfect  surface  wounds ;  iodine  is  as  a  rule 
a  better  disinfectant  for  all  wounds. 

Care  of  the  Sick  Room.  —  Health  officers  also  sometimes  per- 
form an  important  service  by  taking  charge  of  the  disinfection  of 
the  room  in  which  a  patient  has  been  ill  with  a  contagious  disease. 
The  first  thing  to  be  clearly  realized  is  that  the  patient  is  the  real 
source  of  the  germs  in  such  cases.  As  long  as  these  germs  continue 
to  be  discharged  from  him  there  is  no  use  in  doing  anything  to 
his  room.  To  allow  him  to  leave  the  room  before  he  has  ceased 
to  give  off  the  germs  from  his  body,  and  at  the  same  time  to  disin- 
fect his  room,  is  waste  labor,  for  it  does  no  good.  But  after  the 
patient  has  fully  recovered  and  it  is  safe  for  him  to  mingle  with 
other  people,  germs  that  caused  the  disease  may  sometimes  be 
left  in  his  room.  Tuberculosis  germs  live  for  months  in  dark  corners 
or  in  clothing  if  no  attempt  is  made  to  destroy  them.  Hence  it  is 
desirable  that  the  room  and  its  furnishings  which  may  contain  the 
dangerous  germs  should  be  thoroughly  cleansed,  and  all  the  germs 
destroyed.  This  process  is  called  fumigation  or  disinfection. 

First  the  room  is  made  as  nearly  air-tight  as  possible,  all  the 
cracks  are  stuffed  with  cotton,  or  strips  of  paper  are  pasted  over 
all  places  where  air  may  enter.  Then  a  large  quantity  of  some 
germ  destroyer  is  burned  in  the  room,  and  it  is  left  closed  for 
twenty-four  hours. 

The  disinfection  of  rooms  is  not  considered  as  important  as  it 
was  a  few  years  ago.  People  used  to  regard  the  room  as  the  source 
of  the  greatest  danger,  while  we  now  know  that  it  is  the  patient 
who  must  be  guarded  and  kept  from  contact  with  others  until 
he  can  no  longer  give  the  disease.  There  is,  however,  some  danger 
of  infection  from  the  room,  and  so  the  disinfection  of  rooms  is  still 
commonly  practiced.  When  the  patient  is  allowed  to  leave  the  sick 
room  he  should  always  wear  new  clothing  or  clothes  that  have  been 
thoroughly  disinfected  ;  for  the  clothing  he  wore  while  sick  is  much 
more  likely  to  contain  the  disease  germs  than  the  room  he  has  left. 


HOW  THE  SPREAD  OF  EPIDEMICS  IS  CHECKED     411 

Health  Laboratories 

Many  problems  of  public  health  require  the  assistance 
of  people  who  are  especially  trained  in  the  use  of  a  micro- 
scope and  chemical  apparatus.  When  a  health  officer 
wishes  to  find  out  whether  a  child  has  diphtheria  germs  in 
his  throat,  it  is  necessary  to  make  a  proper  examination 


FIG.  114. — A  HEALTH  LABORATORY. 

with  a  microscope.  To  determine  whether  milk  is  adul- 
terated with  water  or  otherwise,  it  has  to  be  analyzed  by 
some  one  who  knows  how.  To  ascertain  whether  a  dog 
who  has  bitten  people  is  really  suffering  from  a  true  case 
of  rabies,  the  brain  must  be  sent  to  an  expert  for  examina- 
tion. To  learn  whether  the  water  supply  is  safe  for  the 
public  to  drink,  it  must  be  analyzed  chemically,  and  the 
number  and  kinds  of  bacteria  in  it  must  be  determined. 
To  know  whether  a  person  is  sick  with  tuberculosis  and 
is  distributing  these  dangerous  germs  around  the  com- 
munity, the  microscope  must  be  used  to  detect  the  germs. 
Many  other  similar  questions  have  to  be  answered  for  the 
public  officials  every  day.  To  answer  them  is  possible 


412  PHYSIOLOGY   AND    HEALTH 

only  for  persons  who  are  accustomed  to  such  work, 
who  are  provided  with  necessary  apparatus,  and  who 
have  time  for  this  purpose.  This  work  is  now  almost 
always  done  in  public  health  laboratories,  where  speci- 
mens are  sent  for  examination,  and  where  experts  are  em- 
ployed. Health  laboratories  have  been  doing  this  work 
for  a  few  years  only,  for  the  simple  reason  that  until 
within  a  few  years  our  doctors  and  scientists  did  not 
know  enough  to  use  a  laboratory  for  this  purpose. 

The  questions  that  these  laboratories  have  to  answer  are 
many,  and  new  ones  are  constantly  arising  every  year, 
as  new  facts  concerning  germs  and  their  distribution  are 
being  discovered.  So  valuable  have  health  laboratories 
become  that  it  would  be  quite  impossible  to-day  to  con- 
trol public  health  without  their  assistance.  It  seems  a 
curious  thing  that  a  person  sitting  at  a  microscope  and 
looking  at  a  specimen  underneath  it  could  tell  that  a 
patient,  perhaps  a  hundred  miles  away,  is  suffering  from 
diphtheria,  tuberculosis,  or  typhoid  fever..  But  not  only 
can  the  laboratory  expert  do  this,  but  he  can  do  it  more 
successfully  in  many  cases  than  the  physician  can,  who  is 
at  the  bedside  of  the  patient  and  can  determine  only 
by  the  general  appearance  of  the  patient  and  his  symp- 
toms. 

These  health  laboratories  are  of  great  aid  to  the  physi- 
cian in  enabling  him  to  determine  what  kind  of  disease 
he  is  to  treat,  and  they  also  are  of  incalculable  aid  to 
public  health  officials  in  helping  them  to  prevent  the 
spread  of  contagious  diseases.  In  addition  to  this,  the 
milk  inspectors  need  the  help  of  these  laboratories  to 
enable  them  to  determine  whether  milk  is  in  a  proper 


HOW   THE   SPREAD   OF   EPIDEMICS   IS   CHECKED      413 

condition  for  use,  or  whether  it  is  adulterated.  The 
water  commissioners  need  them  to  assist  in  telling 
whether  the  water  of  a  city  is  in  a  perfectly  safe  condi- 
tion, or  needs  treatment.  Moreover,  the*  inspectors  of 
foods,  who  are  trying  to  guard  our  market  against  dan- 
gerous, contaminated,  and  adulterated  food,  need  the  aid 
of  such  laboratories. 

Where  a  city  is  large  enough,  it  usually  has  its  own 
laboratory  for  these  purposes.  But  there  are  many 
communities  that  are  too  small  to  be  able  to  afford 
the  money  needed  for  equipment.  Consequently  state 
laboratories  have  been  established  which  are  doing  for 
the  smaller  communities  the  kind  of  work  which  the  city 
laboratories  are  doing  for  the  people  in  the  city.  Our 
whole  country  is  dotted  with  such  public  health  labora- 
tories, where  hundreds  of  people  are  engaged  all  the  time 
in  solving  problems,  for  the  assistance  of  health  officers, 
and  are  therefore  constantly  contributing  a  large  part 
toward  the  improvement  and  maintenance  of  public 
health. 

Health  in  Schools 

Since  parasitic  germs  can  more  readily  pass  from  one 
person  to  another  when  people  are  crowded  together,  it 
is  not  surprising  that  schools  are  frequently  centers  for 
the  distribution  of  contagious  diseases.  The  use  of 
common  textbooks,  borrowing  of  pencils  and  erasers  from 
one  another,  drinking  from  a  common  drinking  cup,  the 
use  of  a  common  towel,  are  some  of  the  easy  ways  by 
which  dangerous  germs  can  be  distributed  from  pupil 
to  pupil.  Diphtheria,  for  example,  is  not  very  common 


414  PHYSIOLOGY   AND   HEALTH 

in  most  communities  during  the  summer  months,  when 
the  schools  have  a  vacation,  and  the  children  are  outdoors 
and  not  crowded  together  in  rooms.  But  just  as  soon 
as  the  school  is  opened  in  the  fall,  there  is  almost  always 
an  increase  in  this  disease,  which  spreads  through  the 
schools.  In  the  same  way  other  diseases  —  measles, 
mumps,  whooping  cough,  scarlet  fever,  and  chicken  pox 
—  are  frequently  distributed  from  home  to  home  through 
the  medium  of  the  school  children. 

The  School  Nurse.  --  Various  means  are  being  adopted 
nowadays  to  produce  a  better  condition  of  health  among 
school  children.  Children  are  often  not  in  the  best 
condition  of  health  when  they  come  to  school.  There 
may  be  trouble  with  the  teeth,  that  prevents  the  children 
from  properly  masticating  food.  Frequently  there  is 
trouble  with  the  eyes,  or  with  the  ears,  or  there  may 
be  some  troublesome  and  serious  skin  or  scalp  disease. 
In  some  of  these  cases  the  troubles  are  contagious.  In 
many  homes  there  is  a  complete  failure  to  understand 
what  these  things  mean,  and  children  suffering  from  them 
are  likely  to  be  sent  to  school  to  mingle  with  other  chil- 
dren. Sometimes  a  little  attention  and  a  simple  remedy 
might  make  these  children  well  and  strong,  while  if 
nothing  is  done  the  trouble  may  continue  for  years,  and 
the  children  may  be  permanently  injured.  For  their 
own  sake  as  well  as  for  the  benefit  of  the  rest  of  the  school, 
it  is  very  desirable  that  all  such  troubles  should  be  dis- 
covered early  and  properly  treated.  As  a  part  of  the 
campaign  for  public  health,  many  communities  there- 
fore engage  school  nurses,  who  make  frequent  examina- 
tions of  pupils.  They  do  not  attempt  the  work  of  a 


HOW   THE   SPREAD  OF  EPIDEMICS   IS   CHECKED     415 

physician  or  give  prescriptions  or  treatment.  They 
simply  discover  defects,  and  suggest  improvements  in 
habits  of  cleanliness,  or  perhaps  in  habits  of  eating. 
They  also  frequently  visit  the  child  in  its  home  to  advise 
parents  to  consult  with  a  physician  or  a  dentist.  In 
other  cases  they  discover  some  contagious  disease  at  its 
very  beginning,  and  are  thus  able  to  prevent  its  spreading 
through  the  schools. 

Epidemics  in  Schools.  —  In  spite  of  all  care  contagious 
diseases  occasionally  find  their  way  into  the  schools. 
It  has  sometimes  been  a  custom  to  close  the  schools  when 
such  epidemics  appear.  The  people  in  a  community  may 
insist  that  the  schools  be  closed  until  the  epidemic  disap- 
pears. In  earlier  years  before  our  scientists  had  dis- 
covered the  best  way  to  handle  such  troubles,  this  was 
about  the  only  thing  that  could  be  done.  But  now  that 
we  have  found  out  how  the  germs  are  distributed  from 
person  to  person,  to  close  the  schools  is  usually  the  worst 
measure  to  take.  This  does  not  mean,  of  course,  that 
children  who  are  ill  should  be  kept  in  school. 

In  the  first  place,  it  means  the  loss  of  much  money  and 
school  time,  and  the  value  of  the  schools  is  too  great  to 
be  thrown  away,  if  it  can  possibly  be  avoided.  But  more 
than  this,  experience  has  shown  that  to  keep  the  children 
away  from  school  does  not  keep  them  from  spreading  the 
diseases,  for  they  are  quite  sure  to  get  together  in  each 
other's  homes,  or  in  public  halls  like  moving  picture 
theaters,  where  the  danger  of  spreading  disease  is  much 
greater  than  it  is  in  the  schools.  Moreover,  when  the 
schools  are  closed,  the  health  officers  and  doctors  cannot 
keep  track  of  the  pupils,  and  when  new  cases  of  the 


416  PHYSIOLOGY   AND   HEALTH 

disease  develop  they  have  no  means  of  discovering  them. 
In  many  families  parents  try  to  conceal  contagious  diseases 
rather  than  to  call  a  physician,  and  thus  the  danger  is 
increased  rather  than  decreased  by  closing  the  schools. 
The  best  way  to  stop  such  epidemics  is  to  keep  the  schools 
open  and  to  carefully  watch  the  children.  If  the  nurse 
and  the  school  physician  do  their  work  well,  it  is  com- 
monly 'possible  to  stop  such  epidemics  promptly.  If 
the  schools  are  closed,  an  epidemic  is  almost  sure  to 
last  longer  than  if  the  schools  were  open. 

QUESTIONS 

1.  Mention  four  methods  by  which  disease  germs  are  carried. 

2.  Why  cannot  a  city  be  kept  as  healthful  as  an  army  camp? 

3.  Why  does  the  health  officer  hang  out  a  quarantine  card  ?     What 
diseases  are  considered  contagious? 

4.  Can  you  give  any  reason  why  typhoid  fever  and  malaria  are 
more  common  in  summer  than  in  winter  ? 

5.  If  a  person  has  the  grip,  will  he  be  likely  to  have  it  again  ?    How 
would  it  be  if  he  had  measles  ?    Scarlet  fever  ?    Diphtheria  ? 

6.  What  are  the  services  rendered  by  a  health  laboratory? 

7.  Why  are  epidemics  frequently  spread  through  the  schools  ? 

8.  What  are  the  duties  of  a  school  nurse  ? 

9.  Why  is  it  a  bad  plan  to  close  the  schools  when  an  epidemic 
appears  in  the  community? 

10.  What  class  of  people  are  most  benefited  by  public  health 
regulations?  Can  you  give  any  reason  why  it  is  these  people  who 
make  most  objection  to  them? 


CHAPTER  VII 
MEETING   EMERGENCIES 

Preparing  to  Meet  Emergencies.  —  Any  one  who  has 
watched  a  skillful  captain  direct  the  handling  of  his  ship 
must  appreciate  that  it  takes  preparation  and  training 
to  enable  one  to  decide,  when  an  emergency  arises, 
what  ought  to  be  done  and  how  it  should  be  done.  The 
captain  does  not  get  his  ability  to  decide  and  act  quickly 
by  reading  about  ships ;  he  had  to  study  navigation,  and 
to  this  study  he  added  long  and  varied  experience.  In 
the  same  way,  we  may  learn  from  this  book  how  to 
induce  artificial  respiration,  but  without  practicing  the 
method  given  we  should  be  very  clumsy  and  uncertain  if 
we  had  occasion  to-morrow  to  try  to  save  a  friend's  life 
by  that  means.  The  motions  described  need  to  be  prac- 
ticed until  one  can  do  them  with  ease  and  confidence. 
So,  top,  with  the  bandaging  of  an  arm  to  check  blood  flow 
from  an  artery.  That  may  be  tried  on  one's  own  arm  or 
better  on  the  arm  of  a  companion,  until  the  fingers  are 
no  longer  clumsy  about  managing  the  compress  and  the 
stick;  that  is,  until  the  neurons  which  may  some  day 
need  to  direct  such  an  operation,  in  earnest,  learn  to  do 
it  quickly  and  readily  when  there  is  no  emergency  to  test 
one's  courage  and  one's  readiness  to  act. 

Accidents.  —  Several  types  of  accident  have  been 
mentioned  in  previous  chapters,  and  suggestions  have 

417 


418  PHYSIOLOGY  AND  HEALTH 

already  been  given  about  emergency  treatment.  These 
suggestions  might  well  be  reviewed  and  put  into  practice 
at  this  time. 

Bleeding  Section  II  Chapter  III 

Broken  bones  Section  II  Chapter  VIII 

Burns  Section  II  Chapter  XIII 

Dislocation  Section  II  Chapter  VIII 

Drowning  Section  II  Chapter  V 

Dust  in  the  eye  Section  III  Chapter  V 

Freezing  Section  II  Chapter  XIII 

Mad  dog  scares  Section  II  Chapter  XIII 

Sprains  Section  II  Chapter  VIII 

Avoidable  accidents  Section  IV  Chapter  II 

Choking 

A  violent  fit  of  coughing  often  means  that  some  small  object  is 
lodged  in  the  windpipe.  Unless  it  is  firmly  lodged  it  may  usually 
be  blown  out  by  coughing.  But  if  it  is  preventing  the  passage  of 
air  to  the  lungs,  it  must  be  quickly  removed  or  the  person  will  die 
for  lack  of  air.  Fortunately  large  objects  seldom  get  stuck  in  the 
windpipe;  they  more  frequently  lodge  in  the  gullet,  where  they 
are  troublesome  enough  but  less  immediately  dangerous,  since  they 
do  not  prevent  breathing.  In  any  case  the  object  causing  the 
choking  must  be  removed,  and  if  coughing  does  not  remove  it, 
the  best  thing  to  do  is  to  have  the  person  bend  his  body  forward 
over  your  knee  or  over  a  chair  and  then  to  slap  him  vigorously  on 
the  back  between  the  shoulders ;  this  is  one  of  the  times  when  it 
is  not  safe  to  wait  for  a  doctor. 

Nosebleed 

The  only  treatment  needed  in  most  cases  of  nosebleed  is  to 
keep  the  person  quiet,  and  give  the  blood  a  chance  to  clot.  Bend- 
ing over  a  basin  increases  the  flow  of  blood ;  the  head  should  be 
held  erect,  and  the  pinching  of  the  nostrils  will  sometimes  hasten 
the  clotting  of  the  blood.  If  the  bleeding  continues  too  long,  it 
is  well  to  apply  ice  to  the  back  of  the  neck  and  to  the  bridge  of  the 


MEETING  EMERGENCIES 


419 


FIG.  115.  —  POISON  IVY. 


nose.  A  plug  of  cotton  put  into  the  nose  is  also  useful.  When  the 
clot  forms,  bleeding  stops;  the  clot  should  not  be  disturbed  for 
some  time;  nor  should  one 
blow  the  nose,  for  that  is  likely 
to  start  the  bleeding  afresh  by 
breaking  the  clot. 

Poisoning  from  Ivy  and  Poison 
Dogwood 

Several  vines  and  shrubs 
produce  an  oily  secretion  that 
is  poisonous  to  the  skin  of  most 
people.  Poison  ivy  is  a  very 
common  vine  which  grows 
over  rocks  and  stone  walls  and 
climbs  up  trees.  In  spring  its 
leaf  is  waxy,  in  the  summer, 
glossy  green,  and  in  the  fall  it 
is  scarlet.  It  is  often  taken 
for  the  harmless  woodbine,  or  Virginia  creeper,  but  remember  that 
it  has  only  three  leaflets,  while  the  woodbine  has  five.  Ivy  has 
yellowish  green  berries ;  woodbine  berries  are  dark  blue. 

Poison  sumac,  sometimes  wrongly  called  poison  dogwood,  pro- 
duces a  more  serious  poison.  It  is  a  shrub  that  grows  chiefly  in 
swamps.  Each  of  its  leaves  has  from  eleven  to  thirty-one  leaflets 
and  it  produces  loose  clusters  of  white  berries.  It  must  not  be 
confused  with  the  beautiful  harmless  flowering  dogwood  which 
grows  on  dry  ground,  and  has  leaves  of  seven  to  thirteen  leaflets 
and  dark  red  fruit. 

The  poison  of  both  ivy  and  dogwood  is  oily  and  works  slowly,  so 
a  thorough  washing  with  strong  soap  and  water  will  often  entirely 
remove  it.  It  is  a  good  plan  therefore  to  wash  the  hands,  arms, 
face,  and  neck  with  soap  and  warm  water  as  soon  as  one  comes  in 
from  a  tramp  in  the  woods  or  fields.  The  poisoning  shows  itself 
by  an  intense  itching,  swelling,  and  blistering  of  the  skin ;  it  is 
very  disagreeable,  but  it  wears  off  in  a  few  days.  When  a  person  has 
once  been  poisoned  he  is  more  likely  to  be  poisoned  a  second  time. 


420 


PHYSIOLOGY   AND   HEALTH 


Poisons 

It  is  a  very  rare  thing  for  one  to  swallow  a  deadly  poison,  but  when 
that  happens  the  treatment  must  be  prompt ;  a  delay  of  even  a  few 
minutes  may  mean  death.  The  precise  treatment  must  depend  upon 
the  kind  of  poison,  but  there  are  some  things  that  should  always  be  done. 

1.  Send  for  a  physician  immediately. 

2.  Cause  the  patient  to  vomit.     This  is  to  remove  as  much  of  the 
poison  as  possible,   and  it  should  be  done  with  all  the  poisons 
mentioned  below  except  the  acid  poisons  and  mercury.     A  tea- 
spoonful  of  mustard  in  a  glass  of  warm  water  should  be  given  the 
patient,  to  induce  vomiting.     Common  salt  may  be  used  instead 
of  mustard.     Immediate  action  is  most  important. 

3.  Administer  an  antidote.     By  an  antidote  is  meant  something 
to  counteract  or  neutralize  the  effects  of  the  poison.     The  most 
common  poisons  with  their  antidotes  are  the  following : 


POISON 
Alcohol 
Acid  poisons 

Alkalis  (ammonia,  lye,  potash) 
Arsenic 

Chloroform  or  ether 
Corrosive  sublimate  (mercury  bi- 
chloride) 
Lead 
Matches  (phosphorus) 

Morphine  (opium,  etc.) 
Strychnine 

Soothing  syrup,  see  morphine. 


TREATMENT 

An  emetic,  followed  by  coffee. 
Baking  soda,  white  of  eggs,  or  lime 

water. 

Vinegar  and  water  or  lemon  juice. 
Emetic,  white  of  eggs. 
Fresh  air,  artificial  respiration. 

White  of  eggs. 

Emetic,  Epsom  salts. 

Emetic,    white    of    eggs,    Epsom 

salts. 

Emetic,  artificial  respiration. 
Emetic,  ether,  spirits  of  ammonia, 

or  white  of  eggs. 


Stings  of  Insects 

The  wounds  made  by  hornets,  wasps,  or  yellow  jackets  come 
from  their  thrusting  into  the  skin  a  sharp,  needle-like  sting  which 


MEETING   EMERGENCIES  421 

carries  with  it  a  veiy  irritating  poison.  Usually  the  sting  is  smooth 
and  can  be  at  once  withdrawn.  The  honey  bee  has  a  barbed  sting 
which  is  left  in  the  wound  when  the  bee  flies  away.  It  should  be 
removed  by  forceps  or  the  point  of  a  knife.  It  is  the  poison  on 
the  sting  that  produces  the  pain;  and  since  this  poison  is  an  acid, 
an  alkaline  remedy  is  needed.  Soda  or  ammonia  applied  to  the 
spot  is  good,  but  nothing  is  really  better  than  wet  mud,  which  will 
soon  relieve  the  pain.  Insects  will  not  sting  if  they  are  let  alone. 

Wounds  of  All  Kinds 

The  method  for  treating  wounds  has  already  been  given,  and  we 
have  seen  the  chief  cause  of  trouble  is  due  to  the  germs  that  get  into 
the  wound  and  may  grow  there,  producing  inflammation,  pus,  blood 
poisoning.  Even  an  unskilled  person  who  will  follow  faithfully  the 
directions  that  have  been  given  can  treat  wounds  more  successfully 
than  a  skilled  surgeon  could  care  for  them  fifty  years  ago,  when  the 
nature  and  habits  of  germs  were  not  known.  One  general  rule  should 
be  emphasized : 

KEEP  ON  HAND  A  BOTTLE  OF  TINCTURE  OF  IODINE 
OR  A  BOX  OF  I.ODINE  OINTMENT. 

With  iodine  one  is  prepared  to  treat  almost  any  kind  of  wound ; 
it  should  be  placed  freely  upon  the  open  wound,  and  may  be  very 
successfully  applied  to  little  sores  and  abscesses  when  they  first 
appear.  If  the  ointment  is  used,  i.e.  iodine  mixed  with  some  oily 
substance  to  give  it  consistency,  it  should  be  rubbed  into  the  skin 
so  that  the  skin  may  take  up  as  much  as  possible.  If  all  wounds, 
scratches,  bruises,  or  breaks  in  the  skin  are  thus  treated  at  the 
very  first,  there  will  be  almost  no  danger  of  inflammation  or  blood 
poisoning,  and  the  wounds  will  heal  quickly. 

A  cut  that  gapes  open  should  have  its  edges  brought  together 
after  the  application  of  the  iodine,  preferably  by  strips  of  sur- 
geon's plaster.  In  a  large  cut  the  sides  may  need  to  be  fastened 
by  stitches,  but  that  requires  a  physician. 


THE  OUTLINES  OF  THE  CHIEF  ORGANS  OF  THE  BODY  IN  POSITION. 

This  diagram  is  designed  to  help  the  pupil  to  locate  these  organs  accurately. 
The  best  way  to  use  it  is  to  draw  the  body  outline  three  times  the  size  of  this 
figure ;  then  draw  the  separate  organs,  as  given  on  the  opposite  page,  three 
times  their  size  there  ;  cut  out  the  organs  drawn  and  place  them  in  the  body 
outline  as  drawn.  The  numbers  show  the  order  in  which  they  can  best  be 
placed.  When  the  pupil  can  place  these  organs  correctly  without  referring  to 
the  diagram,  he  knows  better  than  many  adults  do  where  they  lie  and  how 
they  are  related. 

422 


423 


GLOSSARY  OF  TECHNICAL  TERMS 

The  vowel  symbols  are  those  used  in  Webster's  New  International  Dictionary 

GUIDE   TO   PRONUNCIATION 
a  as  in  am  e  as  in  end  6  as  in  odd  u  as  in  up 


a  as  in  ale 
a  as  in  senate 
a  as  in  ask 
a  as  in  arm 
a  as  in  care 

e  as  in  eve 
e  as  in  event 
e  as  in  her 
i  as  in  ill 
i  as  in  ice 

o  as  in  old 
o  as  in  obey 
o  as  in  orb 
oo  as  in  food 
oo  as  in  foot 

u  as  in  wse 
u  as  in  mute 
H  as  in  wrn 
y  as  in  li//mn 
y  as  in  fiy 

Italicized  vowels  have  the  obscure  sound :  a  as  in  sofa,  e  as  in  recent, 
o  as  in  connect,  and  u  as  in  circws. 

al>-do'm6n.  —  The  lower  cavity  of  the  body  containing  the  stomach, 

intestine,  and  other  organs. 

abscess  (ftb'aBs).  —  A  sore  that  comes  to  a  head  and  discharges  pus. 
ad'e-noids.  —  Useless   growths   sometimes   appearing   in   the   throat 

or  nasal  cavities. 
a-dttl'ter-a'tion.  —  The  debasing  of  a  product  by  the  addition  of  an 

impurity. 

sil-bu'iuen.  —  A  protein,  like  the  white  of  egg. 
al-i-meVta-ry  ca-nal'.  —  A  name  given  to  the  digestive  tract. 
(i-nae'mi-4.  — •  A  condition  in  which  the  blood  is  less  red  than  usual, 

making  a  person  pale. 
anterior  (an-te'ri-er)  root.  — The  branch  of  a  spinal  nerve  that  carries 

messages  from  the  brain  to  the  muscles. 

an'tl-dote.  —  Anything  that  will  counteract  the  effects  of  a  poison. 
an-tl-tox'in.  —  A   substance   which  neutralizes  poison  produced   by 

germs. 

a-6r't«.  —  The  artery  carrying  blood  from  the  heart. 
ar-te'rl-ttl  blood.  —  Blood  that  has  been  purified  by  passing  through 

the  lungs. 

.  —  A  blood  vessel  carrying  blood  away  from  the  heart. 
425 


426  GLOSSARY 

ar-ti-fi'ciSl    rgs-pl-ra'tion.  —  Producing    respiration    by    mechanical 

methods. 
auricles  (6'ri-k'ls).  —  The  chambers  of  the  heart  that  receive  blood  from 

the  veins. 
ba-cil'lus  car'ri-ers.  —  Persons  who  carry  disease  germs  in  their  bodies 

though  they  themselves  are  not  affected  by  them. 
bac-te'ri-a.  —  A  group  of  very  minute  plants. 

ball-and-sock'gt  joint.  —  A  joint  allowing  free  motion  in  all  directions. 
bi'cgps.  —  The  front  muscle  of  the  upper  arm. 
bl-ctts'pids.  —  Eight  of  the   teeth,   four  in  each  jaw,   between  the 

canines  and  the  molars. 
bile.  —  The  liquid  secreted  by  the  liver. 

bl&d'der.  —  The  sac  that  temporarily  holds  the  kidney  secretion. 
bow'els.  —  The  intestine. 

breast  bone.  —  The  bone  in  front  of  the  chest. 
brou'chi.  —  The  branches  of  windpipe  entering  the  lungs. 
ca'nines.  —  Four  teeth,  just  back  of  the  incisors. 
cap'il-la-ries.  —  The  small  blood  vessels  connecting  the  arteries  with 

the  veins. 

car-bo-hy'drates.  — A  name  applied  to  starches  and  sugars. 
car'bon  di-ox'Id.  —  The  gas  produced  by  burning  carbon  in  oxygen. 
car'tl-lage.  —  The  tough  flexible  material  that  forms  the  softer  part 

of  the  skeleton. 

ca'se-in.  —  A  protein  in  milk,  the  basis  of  cheese. 
ca-tarrh'.  —  A  disease  of  the  nasal  cavity  and  throat. 
ce're-als.  —  Foods  obtained  from  grain,  such  as  wheat,  oats,  rice,  etc. 
ceVe-beTltim.  —  The  back  part  of  the  brain. 
cer'e-brfim.  —  The  highest  and  largest  part  of  the  brain. 
co-Sg-u-la'tion.  —  A  change  from  a  liquid  to  a  solid  condition,  such  as 

that  which  occurs  in  the  white  of  an  egg  when  heated. 
com-mfi'nl-ca-ble.  —  Capable   of  being   transmitted  from  person   to 

person. 
cSm'pound  frac'tiire.  —  A  broken  bone  with  the    bone    protruding 

through  the  skin. 
cSm'pre'ss.  —  A  mass  of  soft  cloth  arranged  with  a  bandage  to  produce 

pressure  upon  any  part. 
con-neVtlve   tis'sue.  —  Tendons,   ligaments,   and   other   tissues   that 

hold  parts  of  the  body  together. 
con-ta'gious.  —  The  type  of  disease  that  easily  passes  from  person  to 

person. 


GLOSSARY  427 

c6n-trao/tion.  —  Shortening. 

con-vo-lu'tioiis.  —  The  folds  in  the  surface  of  the  brain. 

cOrds.  —  See  tendons. 

cOrn.  —  A  thickened  portion  of  the  epidermis  (usually  on  a  toe)  caused 

by  friction  or  pressure. 
c6r'pus-cle.  —  A  small  body. 

cra'ni-ttm.  —  The  rounded  part  of  the  skull,  containing  the  brain. 
der'iais.  —  The  inner  layer  of  the  skin. 
di'rt  pkragm. —  A  tough,  muscular  membrane,  separating  the  thorax 

and  abdomen. 

dlph-the'ri-a.  —  A  very  serious  disease  of  the  throat. 
dis-m-feVtioii.  —  Destroying  the  germs  of  disease. 
dis-lo-ca'tion.  —  The  wrenching  of  bones  out  of  position. 
dis-tilled'  liq'uors  (lik'ers).  —  Liquors  made  by  separating  the  alcohol 

from  a  ferm anting  substance. 

duct.  —  A  slender  tube  by  which  secretions  are  carried  from  a  gland. 
dyspepsia  (dls-p6p'sl-a  (sha)).  —  A  disease  of  the  digestive  organs. 
ear'drum.  —  The  middle  cavity  of  the  ear. 
e-mgt'ic.  —  Something  which  will  produce  vomiting. 
en-am'el.  —  The  outer  hard  covering  of  the  teeth. 
gn'zymes.  —  Substances  in  the  digestive  juices  that  give  them  power 

to  digest  foods. 
gp-I-dgm'lc.  —  Any   disease    spreading   among  a   great    number    of 

people. 

gp-I-der'mls.  —  The  outer  layer  of  the  skin. 
gp-i-glot'tls.  —  The  lid  covering  the  opening  into  the  windpipe. 
e-sSph'a-gfis    or  gullet.  —  A  tube  extending  from  the  throat  to  the 

stomach. 
Eu-sta'chl-an  tube.  —  A  tube  leading  from  the  upper   part  of  the 

throat  to  the  middle  ear. 

6x-cre'tion.  —  Waste  material  passed  from  the  body. 
ex'ha-la'tion.  —  Breathing  air  out  of  the  lungs. 
fat  cell.  —  A  minute  drop  of  fat  such  as  exists  in  meat. 
fe'mfir.  —  The  bone  extending  from  the  hip  to  the  knee. 
fer'me'n-ta'tion.  —  A  change  occurring  in  sugar  solutions  by  which 

alcohol  is  produced. 

fer'mgnt'ed  liq'uors.  —  Drinks  made  from  simple  fermented  material. 
fe'ver.  —  A  condition  in  which  the  body  temperature  is  higher  than 

normal. 
fl'bers.  —  Minute  threads,  like  those  of  muscles  or  nerves. 


428  GLOSSARY 

flat  foot.  —  A  condition  of  the  feet  when  the  arch  of  the  foot  has  be- 
come partly  flattened  out. 

f u'el  foods.  —  Foods  used  to  develop  force  or  heat. 
fu'ml-ga'tion.  —  Treating    with    fumes    of    gas,    usually    to    destroy 

disease  germs. 
gall  (gol)  blad'der.  —  A  sac  which  collects  the  bile  secreted  by  the 

liver. 

gan'gll-on.  —  A  mass  of  nerve  tissue  containing  neurons. 
gas'trlc  juice.  —  The  digestive  fluid  secreted  by  the  glands  of  the 

stomach. 

glot'tls.  —  The  opening  from  the  throat  into  the  windpipe. 
glucose  (gloo'kos),  or  grape  sugar.  —  Sugar  found,  or  similar  to  that 

found,  in  fruits. 
gluten  (gloo'tgn). —  A  protein  derived  from  wheat  and  some  other 

substances. 

gul'iet.  —  See  esophagus. 

he-mo-glo'bln.  —  The  red  coloring  matter  in  blood. 
hair   follicles    (fol'I-k'ls) .  —  The    little    pockets    from    which    hairs 

grow. 

hemispheres  (he"m'i-sfers).  —  The  two  halves  of  the  cerebrum. 
hl'ber-nat'mg.  —  Remaining  in  a  dormant,  sleeping  condition  during 

the  winter  months. 
hinge  joint.  —  A  jcint  by  which  the  bones  can  move  in  one  direction 

only. 

Im-mu'nl-t^.  —  Ability  to  resist  disease. 

incinerator  (In-sln'er-a-ter). —  A  furnace  for  burning  garbage,  etc. 
incisors  (In-si'zers).  —  The  eight  middle  froht  teeth. 
incubation  (In-ku-ba'shun)  period.  —  The  time  between  exposure  to  a 

disease  and  the  outbreak  of  the  disease. 

indigestion  (In-dl-jeVchun).  —  Inability  to  digest  food  properly. 
In-feVtious.  —  Produced  by  germs ;    such  diseases  are  also  usually 

contagious. ' 
In-flam-ma'tion.  —  A  condition  of  enlarged  blood  vessels,  accompanied 

by  heat  and  soreness  in  the  inflamed  part. 
In-ha-la'tion.  —  Breathing  air  into  the  lungs. 
In-teVtrne.  —  The  tube  through  which  food  passes  after  leaving  the 

stomach. 

In-vol'un-ta-r^.  —  Without  the  exercise  of  will  power. 
I'so-la'tion.  —  Keeping  a  patient  away  from  other  persons  to  prevent 

his  giving  them  disease. 


GLOSSARY  429 

jaundice  (jan'drs). —  A  disease  due  to  liver  troubles  and  character- 
ized by  a  yellow  skin. 

kidneys   (kid'mz).  —  Organs  for  removing  certain  waste  products. 

lach'ry-mal  duct.  —  The  duct  which  carries  tears  from  the  eyes  to  the 
nasal  cavities. 

lach'ry-mal  gland.  —  The  gland  that  secretes  the  tears. 

lac'te  als.  —  Small  tubes  that  carry  fat  from  the  intestines  to  the 
blood  vessels. 

larynx  (lar'mks),  or  Ad'am's  ap'ple.  —  An  enlarged  part  of  the  wind- 
pipe containing  the  vocal  cords. 

le-gu'mm.  —  A  protein  found  in  beans  and  peas. 

llg'«-ine'nts.  —  Bands  of  white  connective  substances,  which  join  bones. 

lig'a-ture.  —  A  band  drawn  tightly  around  some  part  of  the  body  to 
stop  bleeding. 

lime.  —  A  mineral  substance  for  making  bone. 

llv'er.  —  A  large  red  gland  lying  near  the  stomach. 

lungs.  —  Two  organs  in  the  chest  cavity  which  absorb  oxygen  and 
give  off  carbon  dioxid. 

lymph  (limf)  ves'sel.  —  A  minute  tube  that  carries  lymph. 

ma-Ia'ri-a.  —  A  disease  accompanied  by  chills  and  fever. 

marrow  (mar'o).  —  A  fatty  material  in  the  middle  of  the  long  bones. 

me-dul'lrt.  —  The  lowest  part  of  the  brain. 

me'm'brane.  —  Soft  tissue  in  the  form  of  a  sheet  or  a  layer  covering 
some  part  of  the  body. 

mo'lars.  —  The  large  back  teeth,  twelve  in  number. 

mumps.  —  A  disease  accompanied  by  swollen  jaws  and  cheeks. 

muscle  (mus'?l)  fi'bers.  —  The  microscopic  threads  of  which  muscle  is 
made. 

my'6-sin.  —  A  protein  found  in  meat. 

nar-cot'Ic.  —  A  drug  that  dulls  body  action. 

nasal  (na'zal).  —  Pertaining  to  the  nose. 

nerve  (nurv)  fi'bers.  —  The  microscopic  threads  of  which  a  nerve  is 
composed. 

nerves.  —  Long  bundles  of  fibers  that  carry  messages  in  the  body. 

neu'rons.  —  The  irregular  nerve  cells  that  are  found  in  the  brain 
and  spinal  cord. 

neu'tral-Ize.  —  To  counteract  or  destroy  the  effect  of. 

nutritious  (nu-trish'us).  —  Capable  of  building  up  the  body  or  fur- 
nishing it  with  heat  or  force. 

ox'I-da'tion,  —  A  union  of  some  substance  with  oxygen. 


430  GLOSSARY 

oxygen  (ok'sl-j6n).  —  A  gas  forming  one-fifth  of  the  air. 

pan'cre-as.  —  A  large  gland  which  secretes  a  fluid  to  digest  proteins, 

starches,  and  fats. 

pa-pil'la.  — A  minute,  finger-like  projection. 
p&r'w-site.  —  An  animal  or  plant  that  lives  on  the  body  of  another 

animal  or  plant. 

pa-rot'ld  i> lamls.  —  The  salivary  glands  in  front  of  the  ear. 
pasteurization    (pas'ter-i-za'shiin). —  Heating  food  (milk)  to  a  tem- 
perature of  about  145°  to  destroy  disease  germs. 
pep'sin.  —  An  enzyme  secreted  by  the  stomach. 
plasma  (plaz'ma).  —  The  liquid  part  of  the  blood. 
pneumonia  (nu-mo'nl-a).  — A  very  serious  disease  of  the  lungs. 
pores.  —  Small  openings  in  the  skin  through  which  the  sweat  passes. 
posterior  (pos-te'ri-er)    root.  —  The  branch  of  the  spinal  nerves  which 

carries  messages  from  the  skin  and  muscles  to  the  brain. 
preservatives  (pre-zur'va-tives).  —  Chemical  substances  added  to  food 

materials  to  prevent  their  spoiling. 

pro'te-Ids.  —  Foods  useful  for  building  body  tissue,  such  as  albumen. 
ptomaines  (to'mans).  —  Poisons  produced  in  spoiled  foods  by  bacteria. 
ptil'mo-na-ry  ar'te  ry\  —  The  artery  which  carries  blood  from  the 

heart  to  the  lungs. 
pul'mo-na-ry  cir-cu-la'tion.  —  The  circulation  of  the  blood  from  the 

heart  to  the  lungs  and  back, 
pfilso.  —  A  wave  of  pressure  that  passes  along  the  arteries  with  each 

heartbeat. 
pu'ptl.  —  The  circular  opening  in  the  front  of  the  eye  that  allows  light 

to  pass  into  the  eye. 
pus.  —  A  creamy  matter  which  is  discharged  from  sores,  boils,  and 

other  inflamed  parts  of  the  body. 
pu'tre-fy.  —  To  undergo  decomposition,  resulting  in  very  unpleasant 

odors. 

py  lor'Ic  valve.  —  The  valve  that  closes  the  stomach  from  the  intestines. 
quarantine  (kwor'Sn-ten). —  The  prevention  of  persons  who  are 

likely  to  carry  disease  germs  from  mingling  with  other  people. 
rab'Id.  —  Suffering  from  rabies,  or  hydrophobia. 
re 'fl6x  ac'tions.  —  Actions  that  take  place  without  the  exercise  of  the 

will. 

r?n'ngt.  —  A  ferment  secreted  by  the  stomach,  which  curdles  milk. 
res'pl-ra'tion.  —  The  absorption  of  oxygen  and  elimination  of  carbon 

dioxid  by  the  lungs. 


GLOSSARY  431 

a.  —  The  sensitive  surface  at  the  back  of  the  eye. 
a.  —  The  secretion  that  moistens  the  mouth. 
sal'i-va-ry  glands.  —  The  glands  that  secrete  saliva. 
scar'let  fe'ver.  —  A  disease  characterized  by  a  pinkish  eruption  of 

the  skin. 

se-cre'tion.  —  Material  produced  by  a  gland  for  the  use  of  the  body. 
sem'I-lji'nar  valves.  —  Three  valves  in  the  large   arteries   near  the 

heart. 
s6n's6-ry  nerves.  —  Nerves  that  carry  messages  to  the  brain  resulting 

in  sensations. 
sewage   (sfi'aj). —  The  liquid  material  which  contains   the  various 

discharges  and  wastes  from  our  houses. 
spe'cial  sens'es.  —  The   senses   that   tell   us  of    objects  outside  our 

bodies. 
spi'nal  c6rd.  —  The  part  of  the  nervous  system  which  is  encased  by 

the  backbone. 

spi'nal  nerves.  —  Nerves  arising  from  the  spinal  cord. 
spine.  —  The  name  given  to  the  backbone. 
spleen.  —  A  gland  in  the  abdomen. 

sprain.  —  The  tearing  or  straining  of  ligaments  at  a  joint. 
spa'tnm.  —  Matter  spit  up  from  the  throat  or  lungs. 
starch  grains.  —  The  minute  bits  of  starch  as  they  are  found  in  the 

potato  and  other  raw  foods. 

steVi-Hz-lng.  —  Heating  a  substance  until  all  living  organisms  (bac- 
teria) are  killed. 

stim'u-lfis.  —  A  shock  that  causes  a  muscle  or  other  organ  to  act. 
suf ' fo-ca'tion.  —  Stopping  of  breathing  by  closing  the  windpipe  or  by 

some  other  means. 

taste  buds.  —  The  organs  of  taste  in  the  tongue. 
ten'dons.  —  Bands  of  white  substance  uniting  muscles  with  bones. 
tho'rax.  —  The  chest. 
throat.  —  The  cavity  at  the  back  of  the  mouth  into  which  the  mouth 

and  nose  open. 

ton'sils.  —  Two  rounded  bodies  at  the  back  of  the  mouth. 
ton-sll-ll'tis.  —  A  disease  of  the  tonsils,  accompanied  by  sore  throat 

and  fever. 

tox'In.  —  A  poison  produced  by  a  germ. 
tra'ehe-a.  —  The  windpipe. 
tu-ber-cu-lo'sis.  —  A  disease  produced  by  a  certain  germ,  consumption 

being  its  common  form. 


432  GLOSSARY 

tym-pan'Ic  mgm'brane.  —  A  membrane  stretched  across  the  passage 

leading  to  the  ear. 
u're-a.  —  The  chief  waste  product  of  muscle  action,  secreted  by  the 

kidneys. 

u-re'ter.  —  The  duct  leading  from  the  kidney  to  the  bladder. 
vaccination  (vSk'sI-na'shun). —  Treatment  designed  to  prevent  small- 
pox.    Sometimes  used  as  a  means  of  protection  against  some 

other  diseases. 

valve.  —  A  mechanism  to  open  and  close  a  passage. 
vein  (van).  —  A  blood  vessel  carrying  blood  toward  the  heart. 
vgn-tl-la'tion.  —  The  procuring  of  proper  amount  of  air  in  rooms. 
ven'trl-cles.  —  The  chambers  of  the  heart  that  send  blood  into  the 

arteries. 

vertebra  (vur'te-brd).  —  One  of  the  bones  composing  the  spine. 
vll'll.  —  Little  projections  on  the  inside  of  the  intestine  for  absorbing 

food. 
vo'cal  cOrds.  —  Two  membranes  in  the  larynx  whose  vibrations  produce 

the  voice. 

whoop'Ing  cough.  —  A  disease  characterized  by  violent  coughing. 
yeast.  —  Microscopic  plants  that  cause  the  fermentation  of  sugar. 
yellow  fe'ver.  —  A  disease  common  in  tropical  countries  ;  carried  by 

mosquitoes. 


INDEX 


Absorption  of  food,  65. 
Accidents,  needless,  367-370. 

what  to  do  in  case  of,  418. 
Adenoids,  133. 
Adulterated  foods,  27. 
Air  and  health,  393. 
Air  sacs,  136. 
Albumen,  7. 
Alcohol,  35,  217,  319. 

and  body  heat,  244. 

and  digestion,  80. 

effect  on  the  heart,  120. 
Anaemia,  125. 
Animals,  reasons  for  good  health  of, 

351-357. 

Anopheles,  126. 
Antagonistic  muscles,  208. 
Antitoxin,  168. 
Appetite,  39. 
Army  precautions  for  prevention 

of  disease,  402-403. 
Arteries,  105,  110,  112. 
Artificial  respiration,  159. 
Auricles,  109. 
Axon,  274. 

Bacillus  carriers,  170. 
Bacteria,  91. 
Baking,  84. 
Baths,  247. 

cold,  248  ;  hot,  249. 
Beans,  23,  71. 
Beef  tea,  86. 


Beer,  37. 

Bile,  62. 

Biliousness,  62. 

Bites  of  animals,  267. 

Blackheads,  260. 

Bleeding,  121,  123. 

Blister,  234. 

Blood,  description  of,  101-102. 

pure  and  impure,  113. 

pure,  125. 

Blood  plates,  104,  122. 
Blood  supply,  regulation  of,  117 
Bloodvessels,  290. 

discovery  of,  104. 
Boiling,  84. 
Bone  food,  24. 
Bones,  193,  197. 
Bowels,  61. 
Brain,  277. 
Brain  food,  24. 
Brandy,  38. 
Bread,  12. 
Breakfast,  78. 
Breast  bone,  195. 
Breathing,  145. 

control  of,  291. 
Breathlessness,  146. 
Bright's  disease,  232. 
Broiling,  84. 
Broken  bones,  199. 
Bronchitis,  171. 
Bronchus,  136. 
Bubonic  plague,  129 


433 


434 


INDEX 


Building  foods,  2. 
Burns,  261. 
Butter,  16. 

Callus,  259. 
Candy,  76. 
Capillaries,  111,  113. 
Carbohydrates,  8. 
Carbon  dioxid,  131,  140. 
Cartilage,  206. 
Casein,  7,  16. 
Cereals,  21. 
Cerebellum,  280. 
Cerebro-spinal  system,  277. 
Cerebrum,  278. 

functions  of,  302. 
Cheese,  16. 
Chest,  137,  195. 
Chewing,  42. 
Chicken  pox,  269. 
Chilblains,  263. 
Chocolate,  35. 
Cider,  37. 
Cigarettes,  318. 

Circulation  of  blood,  discovery  of, 
105. 

outline  of,  105. 
Clavicle,  195. 

Cleanliness  and  health,  393-396. 
Clothing,  252. 
Clotting  of  blood,  122. 
Cocoa,  35. 
Coffee,  35. 

Cold  air,  a  tonic,  254. 
Cold-blooded  animals,  241. 
Colds,  170. 
Cold  storage,  29. 
Collar  bone,  195. 
Color  blindness,  332. 
Combustion,  3,  140. 
Compound  fracture,  200. 


Concentration,  306. 
Connective  tissue,  190. 
Consumption,  174. 

cure  of,  179. 

how  spread,  176. 

Contagious  diseases,  92,  404-408. 
Cooking,  82. 
Corn,  21. 
Corns,  259. 
Corpuscles,  102. 
Cortex,  279. 
Cream,  12,  16. 
Culex,  127. 

Daily  ration,  73,  75. 

Deafness,  338. 

Deformities  of  spinal  column,  221. 

Dendrites,  274. 

Dennis,  233. 

Diabetes,  231. 

Diaphragm,  143. 

Digestibility  of  foods,  72. 

Digestion,  41. 

control  of,  291. 
Dinner,  78. 
Diphtheria,  168. 
Disease,  89. 
Disinfectants,  408-410. 
Dislocations,  210. 
Distilled  liquors,  37. 
Distribution  of  disease,  402,  404. 
Drowning,  160. 
Drugs,  89. 
Dust,  176. 

Ear,  structure,  335-336. 

care  of,  337. 
Eggs,  20. 

Emergencies,  instructions  for  meet- 
ing, 417-421. 
Enamel  of  teeth,  48. 


INDEX 


435 


Enzymes,  63. 
Epidermis,  233. 
Epiglottis,  134. 
Esophagus,  53. 
Eustachian  tube,  335. 
Evaporation  of  perspiration,  242. 
Exercise,  147,  213,  223. 
Exhalation,  131. 
Eye,  325. 

care  of,  332. 

compared  to  a  camera,  328. 

muscles  which  move,  328. 

protectors  of,  326. 

Fainting,  120. 

Fat,  absorption  of,  67. 

digestion  of,  64. 
Fatigue,  216,  305. 
Fatigue  poisons,  228. 
Fats,  11. 
Feet,  201. 

Fermented  liquors,  37. 
Ferments,  36. 
Flat  foot,  202,  204. 
Fleas,  129. 

Flies,  as  disease  distributors,  96. 
Food,  amount  needed,  73. 

kinds  of,  6. 

need  of,  1. 

source  of,  15. 
Food    supply,    guarded    by  public 

officials,  389-390. 
Food  values,  12,  87. 
Frost  bites,  263. 
Fruits,  23. 
Fuel  foods,  3. 

GALEN,  104. 
Gall,  62. 
Games,  224. 
Ganglia,  284. 


Garbage,  396-398. 

Gas  poisoning,  162. 

Gastric  juice,  55. 

Germ  diseases,  91. 

Germs,  165. 

Gin,  38. 

Glottis,  133. 

Glucose,  10. 

Gluten,  7,  21. 

Grace  of  body,  218,  224. 

Graham  flour,  22. 

Grains,  21. 

Gray  matter,  279. 

Green  stick  fracture,  200. 

Grip,  172. 

Gullet,  53. 

Gum  chewing,  44. 

Habits,  299. 

Hair,  234,  251. 

HARVEY,  105. 

Health,  rules  for  good,  370-372. 

in  schools,  413-416. 
Health  laboratories,  411-413. 
Hearing,  335-337. 
Heart,  description  of,  108. 

training  of,  119. 

work  of,  110-112. 
Heart  beat,  116,  289. 
Heating  and  ventilation,  154. 
Heat  production  during  sleep,  256. 
Heat  regulation,  239. 
Hemoglobin,  102,  139. 
Hermit  crab,  214. 
Hibernating  animals,  241. 
Hip  disease,  174. 
Hookworm  disease,  97. 
.Hunger,  345. 
Hydrophobia,  268. 

Ice  box,  29. 
Ice  water,  80. 


436 


INDEX 


ill  health,  causes  of,  349-351. 
Immunity,  270. 
Impurities  in  water,  32. 
Incubation  time,  166. 
Indigestion,  65. 
Infectious  diseases,  92. 
Inflammation,  170. 
Influenza,  172. 
Inhalation,  181. 
Instincts,  293. 
Intestines,  61. 
Involuntary  actions,  287. 
Involuntary  muscles,  190,  191. 
Isolation  period,  408. 

Jaundice,  62. 
Joints,  206. 

Kidneys,  diseases  of,  231. 

work  of,  229. 
Kingdoms,  5. 

Lachrymal  gland,  327. 
Lacteals,  68. 
Large  intestine,  64. 
Larynx,  135. 
Legumin,  7. 
Lens  of  eye,  329. 
Ligaments,  207. 
Ligature,  122,  124. 
Liver,  62. 

a  storehouse,  69. 
Lockjaw,  266. 
Lungs,  137. 
Lymph,  113. 

Malaria,  92,  126. 
Marketing,  26. 
3Ieasles,  92,  269. 
Meat,  18. 

digestion  of,  56. 
Medulla  oblongata,  280. 


Memory,  303. 
Milk,  15,  183. 

a  source  of  disease,  95. 
.care  of,  17. 
digestion  of,  56. 
Milk  sugar,  10,  16. 
Milk  supply,  385-389. 
Milk  teeth,  51. 
Mind,  302. 
Mixed  foods,  12. 
Mosquitoes,  126,  129. 
Motion,  18(5. 
Motor  nerves,  283,  324. 
Mouth  breathing,  132. 
Mumps,  167. 
Muscle  fibers,  190. 
Muscles,  186. 
Myosin,  7. 

Nails,  235,  252. 
Narcotics,  315,  319. 
Nearsighted  ness,  331. 
Nerve  fibers,  191,  274. 
Nerves,  282. 
Nervousness,  312. 
Neurons,  273,  297. 

control  of,  287. 

organization  of,  275. 

training  of,  297. 
Night  air,  128. 
Nuts,  24. 

Oatmeal,  22. 

Occupations,      healthful     and     un 

healthful,  361-362. 
Open  air  schools,  150. 
Opium,  316. 

Oxygen,  3,  102,  131,  139. 
Oysters,  disease  distributed  by,  97 

Pancreas,  63. 
Parasites,  91. 


INDEX 


437 


Pasteurization  of  milk,  18. 
Patent  medicines,  90. 
Peanuts,  23. 
Peas,  23. 

Perspiration,  228. 
Plague,  129. 
Pneumonia,  171,  172. 
Poise,  218,  222. 
Poisoning,  227 
Pores,  236. 
Potatoes,  23. 
Preservatives,  30. 
Proteins,  6. 

absorption  of,  67. 

in  food,  13. 

Ptomaine  poisoning,  28. 
Public  drinking  cup,  406. 
Public  halls,  156. 
Public  health  officials,  376^380. 
Pulse,  110. 
Pupil  of  eye,  329. 
Pure  food  laws,  30. 
Pyloric  valve,  55. 

Quarantine,  405. 

Rabies,  268. 
Raising  of  bread,  86. 
Rats,  129. 
Reasoning,  304. 
Recreation,  307. 
Red  corpuscles,  102. 
Reflex  action,  291. 
Reflexes,  acquired,  294. 
Regularity  of  meals,  77. 
Respiration,  131. 
Respiratory  center,  291. 
Rest,  308. 
Retina,  329. 
Ribs,  195. 

changes  in  position  of,  in  breathing, 
144. 


Rice,  22. 
River  water,  34. 
Roasting,  84. 
Rules  for  eating,  79. 
Rum,  38. 

Saliva,  43. 

Sanitary  science,  growth  of,  374-376. 

Scarlet  fever,  269. 

Schoolroom  ventilation,  151. 

Scrofula,  174. 

Second  wind,  146. 

Sensations,  classified,  325. 

Sensory  nerve,  283,  324. 

Sewage,  398-400. 

Shoes,  effects  of  wearing  improperly 

shaped,  201. 
Skeleton,  193. 
Skimmed  milk,  16. 


functions  of,  237. 
Skin  infections,  264. 
Skull,  194. 
Sleep,  255,  309. 

and  digestion,  59. 
Sleeping  rooms,  156. 
Smallpox,  270. 
Smelling,  341. 
Solar  plexus,  285. 
Soups,  85. 

Spinal  column,  193. 
Spinal  cord,  194,  281. 
Spoiled  foods,  19,  28. 
Sprain,  210. 
Spring  water,  32. 
Sputum,  172. 
Starch,  8. 

digestion  of,  57. 
Sternum,  195. 
Stews,  85. 
Stimulants,  217,  315. 


438 


INDEX 


Stomach,  54. 
Suffocation,  162. 
Sugar,  8,  9. 

absorption  of,  67. 

digestion  of,  57,  63. 
Swallowing,  53. 
Sweat  glands,  236. 
Sweating,  229. 
Sympathetic  system,  284. 

Tapeworm,  19. 

Taste,  70,  339. 

Tea,  35. 

Teeth,  and  digestion,  47. 

cleaning  of,  49. 

decay  of,  49. 

Temperature  of  the  body,  238. 
Temperature  sense,  344. 
Tendons,  188. 
Thirst,  345. 
Tobacco,  218,  317. 

effect  of,  on  heart,  120. 
Tonsillitis,  167. 
Tonsils,  133. 
Touch,  343. 
Tourniquet,  124. 
Towels,  250. 
Toxin,  168. 
Toy  pistols,  266. 
Trachea,  133. 
Trichina,  19. 
Tuberculosis,  173. 

how  prevented,  177 

in  animals,  183. 
Typhoid  carrier,  96. 
Typhoid  fever,  94. 
Unused  muscles,  220= 
Urea,  228,  229. 
Ureter,  231. 

Vacations,     wholesome     ways    of 
spending,  363. 


Vaccination,  270,  405. 
Valves,  of  heart,  109. 

of  stomach,  55. 
Variety  in  food,  75. 
Vegetables,  23. 
Veins,  105,  112. 
Ventilation,  150. 
Ventricles,  109. 
Vertebrae,  193. 
Villi,  66. 

Vocal  cords,  135. 
Voice,  135. 

Voluntary  actions,  289,  297. 
Voluntary  muscles,  189,  190. 
Vomiting,  55. 

Walking,  223. 

Warming  up  for  a  race,  118. 
Waste  materials,  64. 
Wastes,  of  city,  396. 

production  of,  in  the  body,  227. 

removal  of,  from  body,  228-232, 
Water,  32. 

a  source  of  disease,  94. 
Water  drinking,  46,  79. 
Water  supply,  381-384. 
Wells,  33. 
Wheat  flour,  22. 
Whisky,  38. 
White  corpuscles,  103. 
White  matter,  279. 
Whooping  cough,  167. 
Windpipe,  133. 
Wine,  37. 

Wounds,  deep,  treatment  of,  265. 
on  feet,  267. 

X-ray,  58. 

Yeast  plants,  36. 
Yellow  fever,  128. 


16 


Y.B  65502 


i    . 


•858866 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


